This reverts commit f68774fd1ad570fef850439ac163b61dc96b98f1. The
original PR broke the sanitizer-aarch64-linux-bootstrap-asan builder:
https://lab.llvm.org/buildbot/#/builders/24/builds/16298
The cause of the failure was exegesis producing inconsistent results
across libc++ implementations when seeded with
'--random-generator-seed=<seed>'. The failing Buildbot does a 2-stage
build, in the 1st stage it builds LLVMs libc++ then builds LLVM with it
in the 2nd stage. The exegesis implementation relies on
uniform_int_distribution which doesn't guarantee consistent results
across implementations.
The tests seeded the RNG because FileCheck can't handle the wrap around
constraint of the register pairs, e.g. { v31.1d, v0.1d }. The test is
updated to no longer rely on '--random-generator-seed'. Unfortunately
the tests aren't particularly good anymore, but not sure what else can
be done for now.
66d41f8483