The spirv-tool project uses some test cases from the tint project, which
was recently merged with the dawn project. This change updates paths
accordingly.
* Use uninstrumented spirv-as for corpus prep
Using an instrumented version of spirv-as for corpus preparation is very
slow, and can also lead to issues where a bug in spirv-as gets picked up
by instrumentation and causes corpus preparation to fail when we would
rather it succeeded despite the bug.
* Disable msan
Disabling msan for now so that fuzzing using other sanitizers can
proceed.
The LIB_FUZZING_ENGINE environment variable is now passed to the CMake
command of spirv-tools as an option, rather than having the environment
variable be queried in the project's CMake files.
Alastair Donaldson