LibTest: Support death tests without child process cloning

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.

Libraries/LibTest/TestCase.h

@@ -110,6 +110,7 @@ private:
 // Helper to hide implementation of TestSuite from users
 TEST_API void add_test_case_to_suite(NonnullRefPtr<TestCase> const& test_case);
 TEST_API void set_suite_setup_function(Function<void()> setup);
+
 }
 
 #define TEST_SETUP                                   \