Add implementations for changes to RuntimeTypeSystem contract
Add SOSDacInterface call into cDac for GetMethodTableName

- Move pointer to Module class
- Replace use of SBuffer abstraction with a simple counted byte memory block
Add metadata details to Loader contract
Add Metadata helper api for use by contracts within the cDAC (and possibly clients of cDAC too)

1. It works now!

- Remove TypeHandleArray and MethodTableArray in favor of contract specific logic

…ime into cdac-methodtable-name

Co-Authored-By: David Wrighton <davidwr@microsoft.com>

mock the additional data and globals

- Add test suite for the DacStreams contract

…name

…reading needs

…ion of contract Loader.GetPath for a future date

1. Rename mcNDirect to mcPInvoke
2. Rename MethodDescClassification to MethodClassification
3. Remove mc prefix from all MethodClassification enum values
4. Move handling of various forms of MethodDescs to using an AsBlah method, and handle the flags in those methods, to make the actual contract methods somewhat simpler.
5. Compute the token eagerly on MethodDesc creation to avoid having to hold a pointer to the Target