Remove legacy build instructions and files from tests directory

[edwardhartnett]

Seems like we have one unit test, and it is being run by CMake and in the CI.

@BoiVuong-NOAA and @kgerheiser are we running the full set of tests from CMake?

If so, let's remove all the files we don't need for that...

[BoiVuong-NOAA]

I do not know about tests from CMake. So, I will not continue to work on test_params_grib2_tbl_new.f90.

[edwardhartnett]

Are you going to add test code for your open PR?

Are there tests in the tests directory that are not being run by CMake?

What is test_params_grib2_tbl_new.f90?

[BoiVuong-NOAA]

I can modify the test code to add some new fields. I think these tests run by CMake. But, We only need test_params_grib2_tbl_new.f90.
The test_params_grib2_tbl_new.f90 uses to test new fields that add in the params_grib2_tbl_new file.