[debuglog] Shutdown debuglog before shutting down system

Prior to this change, we'd sometimes miss the last several log
messages emitted shortly before shutdown. This was a problem for CQ/CI
tests. See INTK-281 for details.

Add function to shutdown the debuglog subsystem and join its
threads (dlog_shutdown).

Call dlog_shutdown as part of graceful shutdown path.

Change core-tests to print magic "success" string only once.

Test: Tested manually as follows:
- Ran on CQ, observed that core-tests now show full output.
- Inserted a panic after dlog_shutdown, verified panic is printed.

ZX-2489 #done

INTK-281 #comment dlog_shutdown

Change-Id: I99f6a61b6afcf6387c4ab28f70db8f33e13a308a

[core-tests] Output distinctive string upon success.

The infra will search for this string to determine success.
See attached bug for discussion.

Bug: INTK-281 #comment
Test: CQ
Change-Id: I2b026b655f1c602cd4c08e3c24463c1ad4503095

[debuglog] Migrate to zx_debuglog_create

Test: cq

Change-Id: Ia7aa2efefd0c1ac0ce3460159a9405d6f0b1777e

[logging] Migrate zircon off zx_log_read and zx_log_write

zx_log_create is trickier. It's essentially a version of
zx_debuglog_create that allows not passing a root resource.

ZX-2184

Change-Id: Ida3d6bacce2c4601a4c6a00fd0cf13c902eb1d41

[utest] Only run core-tests from userboot

ZX-2169 #done

Change-Id: I4b1c80d06a8d34fe639f4f5e9be7bc36d57383c6

[utest] Make unexposed variables static

Change-Id: I016d058e7e83ea0b627ebd4a1da6e4ce97919617

[zx] Magenta -> Zircon

The Great Renaming is here!

Change-Id: I3229bdeb2a3d0e40fb4db6fec8ca7d971fbffb94

[processargs] tidy up naming and numbering

This cleans stuff up ahead of the addition of string tables for
the upcoming PA_NS_DIR and PA_NS_REQ types and the eventual
flattening of PA_MXIO_* to a single type, using subtypes for
protocol.

- Align names with current-day usage
- Organize numbering / ordering around subsystem usage
- Reduce "type" field to 8 bits
- Reserve space for "subtype" field
- Use PA_ namespace and shorter a lot of very long names

Change-Id: I5e59f412c3b9bd79d90f921a248a6d98d4b703bc

[system][utest][core] Fix core-tests for standalone-boot case

The core-tests binary cannot use any shared libraries other
than libc.so and libmagenta.so, because it runs without a
loader service to find shared library images at runtime.

Change-Id: Ibeb57fa76a6466ad8dc53f31122518e9b9020302

[musl][mxio] Move get_startup_handle from mxio to libc

For MG-228: "get startup handles should not live in mxio"

Change-Id: I29fa9199bdc086fb46fc488c18cd968e1e110e15

[syscalls][debuglog] mx_log_create() returns mx_status_t

Necessary work for the uint-ification of mx_handle_t.

Change-Id: I60ab858879d20314b19115e368a5d6ed76278ca1

[magenta][syscalls] provide pseudo syscall mx_job_default()

This is similar to mx_process_self(), but since the job may not
be the job that the current process is a child of, we call it
job_default -- the default job within which the process may try
to create additional processes.

Change-Id: I5169cf91b732de794fc2f9e18a78c2a51030d6c8

[system][utests] Add some job tests

Just a beachead of tests. More to come.

Change-Id: I66d939392e90b75781009a7052f326c4df67e2d7

[magenta][resource] more resource object functionality

- notifications when children are added
- tests for resources in core-tests
- various small bugfixes
- fix user_ptr array copy with offset (oops!)

Change-Id: I78854c4b99602cba8da4e9022bc2516fed13969a

[magenta][syscalls][headers] tidy up syscall structure related headers

For more complex syscalls, there are now sub-headers that declare their
structures and constants which must be included. This avoids pulling
a bunch of stuff into the global namespace whenever anyone needs to make
a syscall and includes magenta/syscalls.h

The magenta/syscalls-types.h no longer exists.

- magenta/syscalls/debug.h for debugger api defines
- magenta/syscalls/exception.h for exception defines
- magenta/syscalls/port.h for mx_port_*()
- magenta/syscalls/log.h for mx_log_*()
- magenta/syscalls/object.h for object info/property defines
- magenta/syscalls/pci.h for mx_pci_*() (ddk use only)

Change-Id: I636c28e4a9a08836d9543b539f236e9d38ecc11b

[system] align license and license banners with Fuchsia

This adjusts the Magenta userspace code to match the prevailing
license in Fuchsia (three-clause BSD), using the same banner
and license text.

Change-Id: I6b6d79435c5dbaa32027888874849e4f47aaa7be

[system][utest][core] Add README.md.

Change-Id: I9bba90729279c5eaff0fb9eca6ef1f227b1104c4

[utest][core] core-tests is now usable to test magenta/runtime standalone

If the kernel is told to run core-tests instead of devmgr, these tests
will run without any userspace device manager, device drivers, io plumbing,
etc.

For example:
./scripts/run-magenta-x86-64 -c userboot=bin/core-tests

Change-Id: Iabe2ea351524daeb067f9380cf4b36498fcdaac0

[utest] Support categories

This will produce single binary from mxr tests and also seperate binary
for each test

Change-Id: I9345fbeab5751dda356cfd47a766c09957211923