ENH: Add Functionality of running only one test file if specified

[adit4443ya]

With this enhancement we can do this

 aditya-trivedi   tests    script_enhance ≢    FC='gfortran' ./run_tests.sh bcast_1.f90 
Received argument(s). Will only compile/run: bcast_1.f90
Compiling bcast_1...
Running bcast_1 with 1 MPI ranks...
 Rank=           0  received integer=           1
Test bcast_1 with 1 MPI ranks PASSED!
Running bcast_1 with 2 MPI ranks...
 Rank=           0  received integer=           1
 Rank=           1  received integer=           1
Test bcast_1 with 2 MPI ranks PASSED!
Running bcast_1 with 4 MPI ranks...
 Rank=           0  received integer=           1
 Rank=           2  received integer=           1
 Rank=           1  received integer=           1
 Rank=           3  received integer=           1
Test bcast_1 with 4 MPI ranks PASSED!

... Running standalone tests took 4 seconds ...

This is because if we are working on making new MREs or Adding new tests then we do not have to run all the tests everytime

[adit4443ya]

I'm Merging it @gxyd Gentle ping