drcachesim.delay-simple test failing on A64

The delay-simple test is now failing every time on A64:

====> FAILURE in debug-internal-64 <====
	code_api|tool.drcachesim.delay-simple =>  Application /var/lib/jenkins/.jenkins/workspace/DynamoRIO-AArch64-Precommit/build/build_debug-internal-64/suite/tests/bin/simple_app (16772).  Internal Error: DynamoRIO debug check failure: /var/lib/jenkins/.jenkins/workspace/DynamoRIO-AArch64-Precommit/core/heap.c:1961 IF_WINDOWS(doing_detach ||) vmh-num_free_blocks == vmh-num_blocks - unfreed_blocks || ((ever_beyond_vmm IF_WINDOWS(|| get_os_version() = WINDOWS_VERSION_8_1))  vmh-num_free_blocks = vmh-num_blocks - unfreed_blocks) 
	code_api|api.static_sideline_FLAKY 

====> FAILURE in release-external-64 <====
release-external-64: 51 tests passed, **** 2 tests failed, of which 1 were flaky, but ignoring 0 for i#2417: ****
	code_api|tool.drcachesim.delay-simple 

@abhinav92003 since you recently change how that works (the flush type, etc.) could you take a look? I think the leak assert reproduces on the TX1.

Xref analysis of when it started failing: https://github.com/DynamoRIO/dynamorio/pull/4529#issuecomment-734293283