Support FIPS feature w/ old compilers

[justsmth]

Description of changes:

• The use of -ffile-prefix-map within the aws-lc-fips-sys build scripts was causing build failures with older compilers. This change conditions the use of the flag on the detection of compiler support.

Call-outs:

• For the FIPS build most, but not all, of the build environment source paths are being removed. Changes to the AWS-LC CMake scripts are likely needed to fully support this.

Testing:

• Added a CI dimension to test older compilers with FIPS feature enabled.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license and the ISC license.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.62%. Comparing base (c358484) to head (d98a3b2).
Report is 96 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #564      +/-   ##
==========================================
- Coverage   95.80%   92.62%   -3.18%     
==========================================
  Files          61       67       +6     
  Lines        8143     9366    +1223     
  Branches        0     9366    +9366     
==========================================
+ Hits         7801     8675     +874     
- Misses        342      420      +78     
- Partials        0      271     +271     

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