some prep work for extdata2g vertical regridding development

[bena-nasa]

Trivial changes in preparation for ExtData vertical regridding work. Please approve.
I've done:

1. changed all rc=status); _VERIFY(status) to the _RC macro in ExtData2G grid comp for readability
2. Added a new driver, it's just like ExtDataDriver.x but rather than run my custom cap, this just exercises the regular cap, but has the "Root" component being the same configurable component ExtDataDriver.x uses. This will let me test changes I need to make to CapGridComp.F90

Types of change(s)

• 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)
• Refactor (no functional changes, no api changes)

Checklist

• Tested this change with a run of GEOSgcm
• Ran the Unit Tests (make tests)

Description

Related Issue

[bena-nasa]

Had to made a library in Tests so the executables would not cause race condition in build