Prior to this change, TransformationReplaceIdWithSynonym was designed
to be able to replace an id with some synonymous data descriptor,
possibly necessitating extracting from a composite into a fresh id in
order to get at the synonymous data. This change simplifies things so
that TransformationReplaceIdWithSynonym just allows one id to be
replaced by another id. It is the responsibility of the associated
fuzzer pass - FuzzerPassApplyIdSynonyms - to perform the extraction
operations, using e.g. TransformationCompositeExtract.
A new pass that gives spirv-fuzz the ability to adjust the memory
operand masks associated with memory access instructions (such as
OpLoad and OpCopy Memory).
Fixes#2940.
A refactoring that separates the identification of an instruction from
the identification of a use in an instruction, to enable the former to
be used independently of the latter.
