C++ Unit Tests cannot be filtered by test file

As a result of SERVER-41809, unit tests have been grouped into large executables. There exists no way to just run the tests associated with a given source file. It is also di

A unit test executable should take a source file filter such that it only executes tests matching a given predicate.

-- source_file arg               Test case source file filter. Specify the substring of the source file                                                            name.