Different identified struct types may have the same name ("").
Previously, these were deduplicated based on their name, which caused
an assertion failure when nesting identified structs:
%0 = type { %1 }
%1 = type { i8 }
declare void @fn(%0)
Reviewed By: gysit
Differential Revision: https://reviews.llvm.org/D156531
18439cfc14