Minor cleanups/modernizations

[JPercival]

• Made locators a final element of CqlException, fixed cases where it was missing
  • Removed logic handling that case
• Removed some code along impossible code paths
• Swapped to var in a few places
• Cleaned up some straggling javax imports.

[github-actions]

Formatting check succeeded!

[codecov]

Codecov Report

Attention: Patch coverage is 83.01887% with 9 lines in your changes are missing coverage. Please review.

Project coverage is 63.18%. Comparing base (fe5c101) to head (dde590a).

Files	Patch %	Lines
.../preprocessor/CqlPreprocessorElmCommonVisitor.java	84.84%	2 Missing and 3 partials ⚠️
.../cqframework/cql/cql2elm/CqlCompilerException.java	57.14%	3 Missing ⚠️
...va/org/cqframework/cql/cql2elm/LibraryBuilder.java	85.71%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #1354      +/-   ##
============================================
+ Coverage     63.14%   63.18%   +0.03%     
  Complexity     6127     6127              
============================================
  Files           468      468              
  Lines         25358    25336      -22     
  Branches       4719     4716       -3     
============================================
- Hits          16013    16008       -5     
+ Misses         7184     7171      -13     
+ Partials       2161     2157       -4     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.