Updates needed for MARBL

[mnlevy1981]

Description

1. Intel compiler complains about gettid being declared a static when building the standalone MOM driver (no impact on CESM)
2. Increase MAX_FIELDS_PER_FILE to 500 because every MARBL diagnostic is added to a single history file when running the test suite, and that adds up to ~475 total fields in the h.bgc.z stream and 405 fields in the h.bgc.native stream

Fixes # (issue)

How Has This Been Tested?
I have run aux_mom and aux_mom_MARBL, and also ensured that the single column tests in components/mom/standalone/examples/single_column_MARBL build and run successfully

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• Any dependent changes have been merged and published in downstream modules
• New check tests, if applicable, are included
• make distcheck passes

[mnlevy1981]

We can't make cesm3_0_alpha03b without this PR merged in, but it can go into alpha03a (it doesn't require any specific tags in alpha03b)

[alperaltuntas]

@jtruesdal, This shouldn't affect FV3, but please let us know if you'd like to confirm that.