[lldb][test] Skip global module cache on Arm/AArch64 Linux (again)

This reverts commit 01c4ecb7,
d14d5215 and
a756dc47.

This removes the logging and workaround I added earlier,
and puts back the skip for Arm/AArch64 Linux.

I've not seen it fail on AArch64 since, but let's not create
more noise if it does.

I've written up the issue as https://github.com/llvm/llvm-project/issues/76057.
It's something to do with trying to destroy a process while
a thread is doing a single sep. So my workaround wouldn't have
worked in any case. It needs a more involved fix.