tests/tcg/xtensa: update test_fp1 for DFPU

DFPU sets Invalid flag in FSR when at least one argument of FP
comparison opcodes is NaN, SNaN for most opcodes, any NaN for olt/ole.
Add checks for FSR and expected FSR values.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
1 file changed