The test file is the single longest test among clang's tests and ends up about
doubling the wall time of clang tests on machines with high number of cores.
The test appears to consist of multiple independent subtests and does not have
to be in one file. Splitting it into smaller parts reduces test time on my
machine from ~80s down to ~45.
See before/after comparison here:
https://gist.github.com/Artem-B/d0b05c2e98a49158c02de23f7f4f0279
This file is still among the longest tests in clang and could use some further splitting, if possible.
Between this and arm-cortex-cpus.c tests there are another 10 seconds we could shave off the test time.