[MLIR] Fix genTypeInterfaceMethods() to work correctly with InferTypeOpInterface

- Change InferTypeOpInterface::inferResultTypes to use fully qualified types matching
  the ones generated by genTypeInterfaceMethods, so the redundancy can be detected.
- Move genTypeInterfaceMethods() before genOpInterfaceMethods() so that the
  inferResultTypes method generated by genTypeInterfaceMethods() takes precedence
  over the declaration that might be generated by genOpInterfaceMethods()
- Modified an op in the test dialect to exercise this (the modified op would fail to
  generate valid C++ code due to duplicate inferResultTypes methods).

Differential Revision: https://reviews.llvm.org/D92414