There are no remaining uses of this class in the framework.
This patch is part of the ongoing migration to strict handling of value categories (see https://discourse.llvm.org/t/70086 for details).
Reviewed By: ymandel, xazax.hun, gribozavr2
Differential Revision: https://reviews.llvm.org/D155922
Defines an equivalence relation on the `Value` type to standardize several
places in the code where we replicate the ~same equivalence comparison.
Differential Revision: https://reviews.llvm.org/D135964
