i#4461: Skip stolen register on drcachesim filter barriers (#4469)
i#4461: Skip stolen register on drcachesim filter barriers (#4469)

Do not try to get the application value of the stolen register on the
jump barrier used for drreg parity in filtered drcachesim
instrumentation.

Enable thread filtering on non-x86: there is no missing support there.

Tested by locally enabling the tool.drcacheoff.burst_threadfilter test
(it is disabled for AArch64 because of the #2007 link failure in some
toolchains), working around #4468 with "-steal_register 25", and
confirming that the drreg failure disappears with the fix here.

This is needed for the forthcoming new global filter for drcachesim
(#4462), in addition to the thread filter feature.  An
enabled-on-AArch64 test should be added as part of that feature to
serve as a regression test here, if #2007 has not been resolved by
then to enable the thread filter test.

Issue: #4461, #4462
Fixes #4461
AmesianX/dynamorio,AmesianX/dynamorio,AmesianX/dynamorio,AmesianX/dynamorio,AmesianX/dynamorio