Speed up benchmarks when run as part of gtest as it does not check data

Speed up benchmarks when run as part of gtest as it does not check data
for correctness, making it only run each benchmark for 1 iteration, instead
of thousands or hundreds of thousands.

Add a separate CI step to crashtest benchmarks without collecting any coverage data.

Activate benchmarks in more arches.

Disable some warnings to avoid errors in compiling google benchmark.

Remove separate benchmark CI job, now included in other jobs instead.