A challenge for getting LibTest working on Windows has always
been CrashTest. It implements death tests similar to Google Test
where a child process is cloned to invoke the expression that
should abort/terminate the program. Then the exit code of the
child is used by the parent test process to verify if the
application correctly aborted/terminated due to invoking
the expression.
The problem was that finding an equivalent way to port Crash::run()
to Windows was not looking very likely as publicly exposed Win32/
Native APIs have no equivalent to fork(); however, Windows actually
does have native support for process cloning via undocumented NT
APIs that clever people reverse engineered and published, see
`NtCreateUserProcess()`.
All that being said, this `EXPECT_DEATH()` implementation avoids
needing to use a child process in general, allowing us to remove
CrashTest in favour of a single cross-platform solution for death
tests.
The underlying CPU-specific instructions for operating on UTF-16 strings
behave differently for null inputs. Add an explicit check for this state
for consistency.
Utf16View currently assumes host endianness. Add support for specifying
either big or little endianness (which we mostly just pipe through to
simdutf). This will allow using simdutf facilities with LibTextCodec.
The one behavior difference is that we will now actually fail on invalid
code units with Utf16View::to_utf8(AllowInvalidCodeUnits::No). It was
arguably a bug that this wasn't already the case.
We have a new, improved string type coming up in AK (OOM aware, no null
state), and while it's going to use UTF-8, the name UTF8String is a
mouthful - so let's free up the String name by renaming the existing
class.
Making the old one have an annoying name will hopefully also help with
quick adoption :^)
