[ARM] Fix some non-portable shell syntax in r233301's tests

[ARM] Fix some non-portable shell syntax in r233301's tests

The "|&" operator isn't POSIX, so it can fail depending on the host's
default shell. Avoid it.

There were also a couple of places that did "2>1", but this creates a
file called "1". They clearly meant "2>&1".

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233309 91177308-0d34-0410-b5e6-96231b3b80d8