add open mips tests

[martyall]

• added halt_address field to VmConfiguration as a way to test for program exit (same trick used by cannon to run open mips tests)
• added test file test_mips_elf.rs and run all the (non oracle) tests in CI that aren't currently failing
• added build mips action, change workflows to use this action since mips artifacts are needed when running complete test suite

Current (ignored) test failures that need to be addressed:

• mul.asm: We have an overflow exception because we are trying to do signed integer multiplication with casting that leads to overflow
• exit_group.asm: it's unclear to me what this program means, but the use of syscall is suspect

[codecov]

Codecov Report

Attention: Patch coverage is 85.71429% with 4 lines in your changes missing coverage. Please review.

Project coverage is 76.31%. Comparing base (343132b) to head (4fa1f26).
Report is 42 commits behind head on master.

Files with missing lines	Patch %	Lines
o1vm/src/cli/cannon.rs	0.00%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2926      +/-   ##
==========================================
+ Coverage   74.66%   76.31%   +1.65%     
==========================================
  Files         259      255       -4     
  Lines       61713    60839     -874     
==========================================
+ Hits        46075    46428     +353     
+ Misses      15638    14411    -1227     

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