CRASH api.startstop on aarch64 GA CI

[derekbruening]

api.startstop failed on a64 in a way I don't think we've seen before, in PR #6925 (which makes no changes to core DR):

https://github.com/DynamoRIO/dynamorio/actions/runs/10483334564/job/29035878258?pr=6925

349: Test command: /opt/actions-runner/_work/dynamorio/dynamorio/build/build_debug-internal-64/bin64/runstats "-s" "90" "-killpg" "-silent" "-env" "LD_LIBRARY_PATH" "/opt/actions-runner/_work/dynamorio/dynamorio/build/build_debug-internal-64/lib64/debug:/opt/actions-runner/_work/dynamorio/dynamorio/build/build_debug-internal-64/ext/lib64/debug:" "-env" "DYNAMORIO_OPTIONS" "-stderr_mask 0xC -dumpcore_mask 0 -code_api" "/opt/actions-runner/_work/dynamorio/dynamorio/build/build_debug-internal-64/suite/tests/bin/api.startstop"
349: Test timeout computed to be: 120
349: in event_post_attach
349: in event_pre_detach
349: <Application /opt/actions-runner/_work/dynamorio/dynamorio/build/build_debug-internal-64/suite/tests/bin/api.startstop (20403).  DynamoRIO internal crash at PC 0x0000aaaaa14c351c.  Please report this at http://dynamorio.org/issues/.  Program aborted.
349: Received SIGSEGV at generated pc 0x0000aaaaa14c351c in thread 20405
349: Base: 0x0000ffffa8444000
349: Registers:	eflags=0x0000000080000000
349: version 10.93.19956, custom build
349: -code_api -stderr_mask 12 -stack_size 56K -signal_stack_size 32K -max_elide_jmp 0 -max_elide_call 0 -no_inline_ignored_syscalls -native_exec_default_list '' -no_native_exec_managed_code -no_indcall2direct 
349: 0x0000ffffa7a9d890 0x0000aaaae14b211c
349: 0x0000ffffa7a9d960 0x0000aaaae14b2434
349: 0x0000ffffa7a9d990 0x0000ffffa841a624
349: 0x0000ffffa7a9d9c0 0x0000ffffa837162c>
348/385 Test #349: code_api|api.startstop ...........................................***Failed