This patch fixes two bugs that arise when a 'defm' inherits from a multiclass
and also from a class with assertions.
Differential Revision: https://reviews.llvm.org/D101626
Differential Revision: https://reviews.llvm.org/D93911
This first step adds the assert statement and supports it at top level
and in record definitions. Later steps will support it in class
definitions and multiclasses.