[X86] Add some initial scheduling tests for generic x86 instructions

These will be using inline asm to ensure we have coverage that we're unlikely to get from lowering of basic ir.

Currently waiting for D39728 to land to add support for scheduler comments for inline asm.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@317698 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed