The previous implementation of the ctype functions assumed ASCII.
This patch changes to a switch/case implementation that looks odd, but
actually is easier for the compiler to understand and optimize.
This replaces the old macros LIBC_COPT_TEST_USE_FUCHSIA and
LIBC_COPT_TEST_USE_PIGWEED with LIBC_COPT_TEST_ZXTEST and
LIBC_COPT_TEST_GTEST, respectively. These are really not about
whether the code is in the Fuchsia build or in the Pigweed build,
but just about what test framework is being used. The gtest
framework can be used in many contexts, and the zxtest framework
is not always what's used in the Fuchsia build.
The test/UnitTest/Test.h wrapper header now provides the macro
LIBC_TEST_HAS_MATCHERS() for use in `#if` conditionals on use of
gmock-style matchers, replacing `#if` conditionals that test the
framework selection macros directly.
This part of the effort to make all test related pieces into the `test`
directory. This helps is excluding test related pieces in a straight
forward manner if LLVM_INCLUDE_TESTS is OFF. Future patches will also move
the MPFR wrapper and testutils into the 'test' directory.
