Unify managed runtime type name parsers (#83484)

Unify managed runtime type name parsers (#83484)

Contributes to #72833 and #77868

The performance effect of this change on typical use of `Type.GetType` like `Type.GetType("MyType, MyAssembly")` is in the noise range. The typical use of `Type.GetType` spends most of the time in assembly loader and type loader. The time spent by parsing the type name is small fraction of the total and the performance improvement is hardly noticeable.

When the type name parser performance is measured in isolation, it is several times faster compared to the existing unmanaged CoreCLR type name parser. For example:
```
Type.GetType("System.Object, System.Private.CoreLib",
       assemblyResolver: (an) => typeof(object).Assembly,
       typeResolver: (assembly, name, ignoreCase) => typeof(object));
```
is about 3x faster with this change on CoreCLR.

Co-authored-by: Aaron Robinson <arobins@microsoft.com>