[cDAC] Investigate perf of typehandle lookup by name

As of https://github.com/dotnet/runtime/pull/120114 the cDAC does a brute force linear scan of all typedefs in a module to look up a typehandle by name. This is as opposed to the native implementation that does a hash based lookup in the EEClassHashTable. We should look into the performance impact of this and ways to improve the cDAC implementation, including through exposing the runtime algorithm to the cDAC and/or simplifying the runtime algorithm to make it easier to expose.