Add 32 bit test for Jenkins & MTT

[bwbarrett]

As discovered in #4146, we don't do any CI tests for 32 bit builds. Just adding -m32 to the compiler flags should be sufficient to smoke test so that we catch issues before MTT. Likewise, Absoft is currently the only 32-bit MTT test; AWS will add one to its suite.

[awlauria]

OMPI decided to disable 32bit support per #11248. Closing.