ASSERT signal marker invariants in histogram.offline test on AArch64

Xref #2899 where this test hangs.

This is a new assert on signal marker invariants and it just fired:

http://139.178.83.194:8080/job/DynamoRIO-AArch64-Precommit/887/console
```
171/176 Test #168: code_api|tool.histogram.offline .................***Failed 2.98 sec
Running cmd |/var/lib/jenkins/.jenkins/workspace/DynamoRIO-AArch64-Precommit/build/build_debug-internal-64/bin64/drrun;-s;90;-quiet;-debug;-killpg;-stderr_mask;0xC;-dumpcore_mask;0;-code_api;-t;drcachesim;-offline;-subdir_prefix;tool.histogram.offline;--;/var/lib/jenkins/.jenkins/workspace/DynamoRIO-AArch64-Precommit/build/build_debug-internal-64/suite/tests/bin/pthreads.ptsig|
Running postcmd |/var/lib/jenkins/.jenkins/workspace/DynamoRIO-AArch64-Precommit/build/build_debug-internal-64/clients/bin64/drcachesim;-indir;/var/lib/jenkins/.jenkins/workspace/DynamoRIO-AArch64-Precommit/build/build_debug-internal-64/suite/tests/tool.histogram.offline.pthreads.ptsig.03302.8806.dir|
Running postcmd2 |/var/lib/jenkins/.jenkins/workspace/DynamoRIO-AArch64-Precommit/build/build_debug-internal-64/clients/bin64/histogram_launcher;-test_mode;-trace_dir;/var/lib/jenkins/.jenkins/workspace/DynamoRIO-AArch64-Precommit/build/build_debug-internal-64/suite/tests/tool.histogram.offline.pthreads.ptsig.03302.8806.dir/trace|
CMake Error at /var/lib/jenkins/.jenkins/workspace/DynamoRIO-AArch64-Precommit/suite/tests/runmulti.cmake:106 (message):
*** postcmd2 failed (Child aborted): histogram_launcher:
/var/lib/jenkins/.jenkins/workspace/DynamoRIO-AArch64-Precommit/clients/drcachesim/tests/trace_invariants.cpp:143:
virtual bool trace_invariants_t::process_memref(const memref_t&): Assertion
`memref.instr.tid != pre_signal_instr.instr.tid || memref.instr.addr ==
pre_signal_instr.instr.addr || memref.instr.addr ==
pre_signal_instr.instr.addr + pre_signal_instr.instr.size ||
memref.instr.addr == app_handler_pc ||
type_is_instr_branch(pre_signal_instr.instr.type) ||
pre_signal_instr.instr.type == TRACE_TYPE_INSTR_SYSENTER' failed.

***
```