runtime: tiny allocator can keep allocations alive longer than expected

[DanielMorsing]

As seen in issue #76007, the tiny allocator can keep allocations alive longer than expected. This isn't a big issue with regards to memory use (it is kind of why we have the tiny allocator in the first place) but for objects that have special records like secret allocations and weak handles, it can prevent cleanup actions from occurring.

This issue is for the larger class of problems. Gives us a place to cite whenever we put in workarounds.

[randall77]

We were just talking about this. I have a doc for a possible solution: https://docs.google.com/document/d/1CNp6RIVusOjxS_PrGGybfR28AI3kReTjx4fxIVvwydk/edit?usp=sharing

The other possibility is to add some tiny size classes.

Having a place to record workarounds is great, that way when we fix this issue we can undo the workarounds.

[mknyszek]

We currently have 2 (other) workarounds, one with weak handles, and one with the argument allocation for AddCleanup.