Unify instruction set definition (#33730)

Unify instruction set definition (#33730)

* Unify instruction set definition
- Build simple DSL to describe the instruction set support of the compiler/jit/etc
- Parse DSL and produce data structures useable throughout our compilation environment
- This is in support of adding more granular instruction set support to crossgen2, but this change is pulled out into its own PR to ease reviewing cost
- Make it hard to mess up 64bit instruction set variants by adding helper function to fill them in.
- Add 64 bit variant names to 32bit instruction set enum to remove the need to add a large number of #ifdefs to the jit