ISA-based refactor to move OST1 into a submodule

[Jbalkind]

This is a large-looking refactor that actually doesn't affect that many places in the repo. I moved the OST1 core into a submodule and the SPARCv9 tests into a submodule, so there are a large amount of deletions (new record! 11.5M lines of deletions). This moves the tests around so they're separated by ISA under piton/verif/diag/ and there are a bunch of headers that got cleaned up with some headers and modules moved under piton/design/chip/tile/sparc

This also requires -ost1 to be passed to sims if using the OST1 core. This fixes an issue with sims regressions where it was including -ost1 even when -ariane or -pico were set but it also changes the expected API to sims. I still need to change the README accordingly to make this clear to users

Also the submodules are currently set to not update. However, it requires some weird incantation to git to actually make it instantiate the submodule. I might undo that part. Overall this PR should make shallow repo clones really fast because a huge amount of code has been moved out of the repo

Little more detail:

• Refactoring ISA tests by ISA
• Moving sparcv9 tests into sparcv9-ost1-tests submodule
• Cleaning up headers, moving OST1 headers into sparc/include/
• Moving TRI transducers into sparc/ and pico/
• Moving FPU, common files into sparc/
• Adding hierarchy layer sparc_tri to simplify tile

This will require some verification to be sure I didn't break anything before we merge