Rollup merge of #147179 - Walnut356:template_lookup, r=Mark-Simulacrum

[DebugInfo] Fix container types failing to find template args

This is a less pervasive (but also less powerful) alternative to rust-lang/rust#144394.

This change *only* provides benefits to container types on MSVC. The TL;DR is that nodes that don't populate/aren't discoverable in the PDB for various reasons are given an alternate lookup path that generates the nodes by acquiring the base-type via some gross string manipulation and then asking clang for the node it wants (e.g. `"ref$<i32>"` -> `"i32"` -> `target.FindFirstType("i32").GetPointerType()` -> `i32 *`, which is a valid type for the container to use)

The before/afters are the same as in the above PR's `*-msvc` LLDB screenshots. This works as a stopgap while the above PR is evaluated, but I think that PR is still a much better solution.

Author: Zalathar