get_dynamo_library_bounds sometimes does not correctly find bounds

Created by: Carrotman42

Internally we have a heisenbug which is causing a hang on static detach via dr_app_stop_and_cleanup_with_stats. (Given a fixed compilation/configuration for a specific application the bug is always or never there, but we do not know exactly what compiler feature/runtime configuration is causing the bug to show up: the bug keeps showing up and disappearing depending on where we are sync'd in the source history.) This bug tracks its resolution in relation to DR core code.

I was able to show that when there is a detach hang, get_dynamo_library_bounds is not "correctly" discovering the full bounds of DR code; that is, in one instance the bounds were found to be [0x13200000, 0x1d600000) whereas dr_app_stop_and_cleanup_with_stats had an address of 0x131eb110.

It is unclear at this point if the bug is truly related to the code layout of the binary (e.g. the layout algorithms just so happen to place dr_app_stop_and_cleanup_with_stats far away from all other DR code) or if it's related to a bug in get_dynamo_library_bounds (e.g. not correctly handling some edge case in its scanning and heuristics).

xref PR#3359, which was also related to debugging this issue.