[compiler-rt] Fix test ifdefs and XFAILs (#160687)
This fixes the ifdefs added in
e9e166e54354330c474457711a8e7a7ca2efd731; we need to include int_lib.h
first before we can expect these defines to be set.
Also remove the XFAILs for aarch64 windows. As this test now became a
no-op on platforms that lack CRT_HAS_128BIT or CRT_HAS_F128 (aarch64
windows lacks the latter), it no longer fails.
