glibc nptl/tst-cancelx18 test fails with GCC 9.2 on Arm 32-bit

[Florian Weimer]

I think since the upgrade to GCC 9.2 in Fedora, the glibc test
nptl/tst-cancelx18 (which is built with -fexceptions) fails on the Arm
32-bit architecture (and only there).  I'm not 100% certain that it's
caused by the GCC update, but the patterns of failures and passes
strongly suggests that.

I don't know the proper name for the exact 32-bit Arm variant Fedora
uses.  Its armv7 with hardware floating point, I think.

I'm trying to get a lab machine to debug this further, but in the past,
that was difficult.

Thanks,
Florian