[PATCH] [mips][msa] Build all the tests in little and big endian modes and correct an incorrect test.

[Daniel Sanders]

  On the '-' vs '_' point, I can see I've been fairly inconsistent on that in the MSA tests. I'll change the filenames with underscores to use dashes in a future patch if that's ok.

http://llvm-reviews.chandlerc.com/D1972