change some associate block to fix GNU crash

[weiyuan-jiang]

gfortran crashes at blocks that associate an allocated string. Those blocks are changed to fix the crash. There are some minor cleanups in this PR too.

Description

Related Issue

Motivation and Context

How Has This Been Tested?

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Trivial change (affects only documentation or cleanup)

Checklist:

• I have tested this change with a run of GEOSgcm (if non-trivial)
• I have added one of the required labels (0 diff, 0 diff trivial, 0 diff structural, non 0-diff)
• I have updated the CHANGELOG.md accordingly following the style of Keep a Changelog

[atrayano]

The variable 'extension' has not been initialized yet when used in the __ASSERT at line 4852

[mathomp4]

Note: I'm going to tag @tclune here. I think he is more a fan of snake case (parent_gc) than camel case (parentGC). So he might be doing a bit of a posteriori work on this...

[weiyuan-jiang]

Here parentGC is just a little bit more consistent among several related subroutines. I agree the snake style makes more sense in Fortran in general.

[tclune]

Already done, but we often have to preserve existing oddities with argument names for backwards compatibility. Probably not even worth risking for MAPL 3 unless someone is very confident ...