spirv-fuzz features transformations that should be applicable by
construction. Assertions are used to detect when such transformations
turn out to be inapplicable. Failures of such assertions indicate bugs
in the fuzzer. However, when using the fuzzer at scale (e.g. in
ClusterFuzz) reports of these assertion failures create noise, and
cause the fuzzer to exit early. This change adds an option whereby
inapplicable transformations can be ignored. This reduces noise and
allows fuzzing to continue even when a transformation that should be
applicable but is not has been erroneously created.
There was a lot of code in the codebase that would get the dominator
analysis for a function and then use it to check whether a block is
reachable. In the fuzzer, a utility method had been introduced to make
this more concise, but it was not being used consistently.
This change moves the utility method to IRContext, so that it can be
used throughout the codebase, and refactors all existing checks for
block reachability to use the utility method.
