While converting unittest targets from SCons to Bazel, I accidentially removed 2 unittest definitions from the SConscript files. The definitions must remain present in SConscript files even when empty.

We need to re-add the following stubs:

• op_msg_fuzzer_fixture_test (removed by SERVER-98028)
• tools_workload_characteristics_test (removed by SERVER-98222)

Additionally we should add the tag compile_requires_large_memory_gcc when compiling the mongotrafficreader executable, and remove its exec_properties instead, as mentioned in SERVER-98222.