Fix caching EH clause type handle problem in a conservative fashion (#40493)

Fix caching EH clause type handle problem in a conservative fashion (#40493)

This caching was intended to improve performance of repeatedly catching exceptions. As it happens, the critical section that was being used to protect the cache could trigger a GC, and cause a failure under stress. However, some years ago, the eh clause as operated on by the ResolveEHClause method was changed to be a copy of the EHClause stored during the JIT operation, and thus the caching efforts done in this function did not provide value, and in fact are a minor source of multithread scaling concerns.

- Remove the dynamic caching. (Note, the TypeHandle member variable and the HasCachedTypeHandle function, are still used for LCG dynamic methods.)
- Rename the critical section used to protect the cache, as it is now only used to protect from loading multiple copies of the JIT.