Preprocessor: fix __OPTIMIZE_SIZE__ and -Oz

Add some tests for __OPTIMIZE_SIZE__ and  __NO_INLINE__,
removing the superfluous copies in the target-specific
tests, since it's target-independent.

This uncovered a bug in the handling of -Oz: it would
attempt to store the value 2 in the 1-bit bitfield OptimizeSize,
leaving a value of 0 and never defining __OPTIMIZE_SIZE__.

llvm-svn: 161495