[test-suite] Suppress FP_CONTRACT due to command line changes planned in D74436
The dependent clang patch changes the default setting for ffp-contract to true,
and that causes about 20 test-suite LNT tests to fail on X86. This patch
modifies the build settings to these tests to suppress FP_CONTRACT and
allows the tests to pass.
Reviewed By: Andy Kaylor, segpop, rengolin, jdoerfert
Differential Revision: https://reviews.llvm.org/D102861