swift

2a76fa46 - [GSB] Ensure that we have superclass constraints from merged equiv class.

[GSB] Ensure that we have superclass constraints from merged equiv class. Fixes one recently-found crasher. (cherry picked from commit e256a9d8dfa376c86dc4600f2391ebcc8208bf70) (cherry picked from commit f72fec0c52ae786ae53dfb50ca474f3a2e578e85)