This removes most of the #ifndef ARM32 directives so we get more
thorough testing. It still uses fewer iterations due to running on
Qemu, but I did manually check to be sure that the tests pass without
any special casing at all.

BUG= https://bugs.chromium.org/p/nativeclient/issues/detail?id=4076
R=jpp@chromium.org, kschimpf@google.com

Review URL: https://codereview.chromium.org/1708903002 .