* [Stdlib] Add some prespecializations to the stdlib
This adds prespecializations for commonly used types to the stdlib
* Add false positives to ABI checker ignore list
* Update multithread_module.swift
* Update multithread_module.swift
* Update multithread_module.swift
Previously, metadata prespecialization for classes only occurred when
all of a specialized generic class's ancestors were themselves generic.
Here, that requirement is lifted so that generic classes with concrete
ancestors are also eligible for prespecialization.