Remove unused variables causing compilation warnings #100

Job	Run time
cmake-integration-tests (off, ubuntu-latest)	9s
tests	13s
cmake-integration-tests (instrumentation, ubuntu-latest)	16s
bazel-integration-tests (off, ubuntu-latest)	18s
cmake-integration-tests (walltime, codspeed-macro)	1s
bazel-integration-tests (walltime, codspeed-macro)	23s
bazel-integration-tests (instrumentation, ubuntu-latest)	17s
	1m 37s

Provide feedback