[kernel] Dispatchers and most kernel objects lockdep instrumented.

- Convert SoloDispatcher to a CRTP template type similar to
PeerDispatcher. This makes the lock classes for different solo
dispatchers distinct.
- Instrument the locks for all dispatchers.
- Instrument the locks for all kernel objects except those that
lock the thread_lock.

Bug: ZX-23
Test: k ut all and system/test/* pass + manual stress testing.

Change-Id: I8106c04911e47ea15ccce8e7abd5fbd62adfa6fe

[dispatchers][peers] Centralize the on_zero_handles peer resetting

Instead of requiring all overloads do it, just do it and call a
different function.

Test: All the recently introduced peer lifetime tests pass.

Change-Id: Ib6be480de0fdd4668a35354fc3cd9fdc963bb87a

[syscalls] Update parameter types and names

This CL updates the parameter types and names for a number of syscalls
to match the Zircon System API rubric. There's more work to do to make
all the syscalls conform to the rubric, but this change is a start.

Change-Id: I218ac5e7e0cbd80a8c69fef7891ad40b78b6b407

[fifo] zx_fifo_read/write bytes->elems migration, part 5

Remove the _old compat shims

ZX-1951 #done

Change-Id: Icece05ec5d47d2eb0a73e7fcba4dbed45e866d4f

[fifo] zx_fifo_read/write bytes->entries migration, part 3

Change signatures of zx_fifo_read/write to take the number of elements
plus the element size instead of a single byte size parameter and update
the docs.

Also mark _old shims as deprecated.

ZX-1951 #comment

Change-Id: I1ad71df760e609e9540e7c332fae156d18341023

[dispatchers] Deduplicate peered user_signal() implementations

Change-Id: I0cb3e07848e92ccee4eb87fa885e7c64a883d71c

[fifo] Return ZX_ERR_PEER_CLOSED from zx_fifo_read.

I was seeing zx_fifo_read return ZX_ERR_SHOULD_WAIT instead of
ZX_ERR_PEER_CLOSED.

Change-Id: I287097db75fad64a9910f6b2d695659977a6402e

[dispatcher] Small cleanups

1. Make the holder RefPtr const.

2. Rename the other_ ptr to peer_ to be consistent with peer_koid_ and
PeeredDispatcher.

3. Share the peer_ ptr directly in the PeeredDispatcher.

Change-Id: I8176cb0daa9ff2a5253de9626de6c8f4c2532781

[dispatcher][peers] Share the implementation of peered get_related_koid()

Change-Id: I3c507e08b2a058e38d5d374434801c3dbfbaa3a8

[fifo] Use only the shared locked in fifo dispatchers

Change-Id: I91f5e3039e403e1e2728d4fc11f8e13a407a79b5

[dispatchers] Introduce peered dispatchers

Currently, several zircon dispatchers refer to their peers. These
include channels, sockets, fifos, and event pairs. These objects refer
both to their internal data as well as their signal state bits, as
well as their peers.

For a concrete example, consider zx_channel_write(h0, ...) on a
channel with endpoints h0 and h1. This of course modifies the message
packet buffer associated with h0. But it may also cause h1 to go from
unreadable to readable, so the signal state bits need to be updated.

Currently, this is accomplished by having separate data and signal
locks in the dispatchers, and taking them in a certain order. For the
channel write example, this is

1. h0 data lock
2. h1 data lock
a. h1 signal lock
b. h0 signal lock

where the indentation signifies scope (i.e. signal locks are taken
while holding signal locks.

For most other dispatcher kinds, the data and signal locks were
straightforwardly collapsed. The same approach (just having 1 lock and
not otherwise modifying locking call sites) does not work for peered
objects because of deadlock. The next easiest thing (dropping one
side's lock before taking the other) breaks the atomicity of the data
and signal updates.

Thus we introduce a method to share one lock between both ends of a
channel. The locking pattern for channel write changes to

1. h data lock
a. h1 signal lock
b. h0 signal lock

Subsequent CLs can then remove the per-peered-type signal locks, and
make it simply

1. h lock

When benchmarked, this approach reduced the zircon_benchmarks for
peered objects by reasonable amounts. For example, the
Channel/Write/64 bench went from about 650ns to 580ns on my NUC.

Change-Id: Ifb05ff75501cb2cea1bf0a506b6f647e788b47f3

[user_ptr] Enforce IN/OUT/INOUT semantics

Change-Id: I54e92ed999c1965114aa80aeffe8d0fc16184b40

[dispatcher][state_tracker] Move the state tracker into the dispatcher

Note that all access to the old StateTracker functionality is still
mediated by the has_state_tracker function. This is used to e.g. allow
only certain objects to be user signalled.

Change-Id: If9d0413eb131c6e7d70ea19c1ed928f7bf566cc8

[fifo] Make FifoDispatcher operations take user_ptr

Change-Id: I0a6d87b5945a7d09ec61191b9310b74382a31a5a

[fifo] Remove generic read/write behavior in fifos

These now only read to or write from a user_ptr. The pluggable
behavior is no longer needed.

Change-Id: Ib79b8ae416aaafbdf838f0bf7c5a1582af2ebba0

[fifo] Remove unused FifoDispatcher methods

I believe these were intended for hypervisor use. But that now uses
ports for event delivery.

Change-Id: I78f185648f75030cb04a08e5f2121ceb79c2253a

[zx] Magenta -> Zircon

The Great Renaming is here!

Change-Id: I3229bdeb2a3d0e40fb4db6fec8ca7d971fbffb94

[zircon][mxtl->fbl] Rename mxtl to fbl

Change-Id: Ie21b6498e1bfb0a7fa0315e40b9e5c3ee78646be

[lib/magenta] Rename kernel/lib/magenta to kernel/object

TODO: Rename magenta.{cpp,h} and other instances of "magenta" in this
module.

For MG-1091 "Rename kernel/lib/magenta"

Change-Id: I2abc316f543798e00d3a4d1c2c83195da26e6836