Fix crossgen with large version bubble enabled

Fix crossgen with large version bubble enabled

This change fixes about 1483 failing Pri-1 tests when they are
crossgen-ed with large version bubble enabled. Only one failing test
remains.

60% of the test cases were failing due to a failure to find generic
interface in an interface map due to the fact that the interface type
was being passed in canonical form.
The remaining 40% were tests using constrained calls. We were missing
the ENCODE_METHOD_SIG_Constrained in the method flags.