[kernel] Move unittest.h to include/lib/unittest/

Move unittest.h deeper in the tree so include statements will say:

Change-Id: I85cb027a53530cd2003d813f004aaea3509f9f40

[kernel][unittest] Remove unused "void* context" argument from test cases

This argument is always NULL.

This argument was part of an init/cleanup feature that was unused and
that was removed.

Change-Id: I997a268be10c6837b2d7529fb92c2df2e3bab814

[kernel][unittest] Remove unused init/cleanup function parameters

None of the in-kernel test cases provide init or cleanup functions.
They all pass NULL to UNITTEST_END_TESTCASE() for those parameters, so
we can remove those parameters. Note that unittest.c wasn't actually
using the cleanup function.

Change-Id: I0332bc5c870deec8a021f543ec2c31ef95c30d0f

[kernel][unittest] Rename REQUIRE_* to ASSERT_* to match userland's unittest.h

This is also more consistent with gtest.

Change-Id: Ic39e75c41a55ca5cba2d09cb920c7cd1c1c7a899

[zx] Magenta -> Zircon

The Great Renaming is here!

Change-Id: I3229bdeb2a3d0e40fb4db6fec8ca7d971fbffb94

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

Change-Id: Ie21b6498e1bfb0a7fa0315e40b9e5c3ee78646be

[kernel][status] Convert the rest of kernel/lib to mx_status_t

Change-Id: Iba1bb7024bcefa7c5e3ee58b02d0be758c6545ae

[mxtl[[count_of] Prefer mxtl::count_of to countof in C++

Change-Id: I1fcbc61031df91542fc60d224b9c24e9b3b260cb

[kernel] Add copyright notices

Change-Id: Ic8e4bc0395dc916097ea436f18cd3e36dc0d9029

[unittest] Use ASSERT_NE()/EXPECT_NE() instead of ASSERT_NEQ()/EXPECT_NEQ()

This is to make the interface more consistent with gtest, which uses
the _NE suffix rather than _NEQ for "not equal".

Change-Id: Ic03fda7322ab79cbd806c8f849b6956d201c6d45

[kernel][lib] Use the new MX_OK and MX_ERR_* names

Change-Id: I436bb0728838729bef6e20a6db0e8ce6a96b5534

[kernel][arm] Integrate memory limit lib into platform

- Enable kernel.memory-limit-mb for all ARM64 platforms
- Remove a header that slipped into memory_limit.cpp
- Fix a typo in memory_limit tests pertaining to rpi3 memory

Change-Id: Ia3596a53c920b7c171f7230ff9f7d9dd512f1acc

[kernel] Add library to restrict kernel memory

This library takes memory ranges of base / size along with a
configuration specifying where the kernel and ramdisk were loaded
in memory. Using that information, it checks for a predefined memory
limit being imposed on the system and returns io vectors necessary
to fulfill that requirement, but still maintain space for the kernel
and ramdisk. If the ramdisk is too large to fit within the memory
specified then the limit will be expanded to fit the ramdisk to
prevent difficult to debug crashes / OOM situations. The library will
use the fewest number of vectors possible so that pmm arenas can be
kept to a minimum.

Change-Id: I184db47f9323c5aa22471cd396731a2f83a4729c