In ac76bc1145, I added a few volatiles to work around ctrig_test
failures with {inf,inf}. This is not necessary anymore now, since in
3b00222f15 we added -fp-exception-behavior=maytrap for clang >= 10 in
libm's Makefile. (The flag tells clang to use stricter floating point
semantics, which libm depends on.)
PR: 244732, 254911
Fixes: ac76bc1145
MFC after: 3 days