fixes #157504

This changes adds the emulation we need for IsNaN, IsNormal, & IsFinite
This change only applies these emulations to the llvm.is.fpclass cases
of fp16.

Since there is no DX intrinsics yet for these cases, applying the
emulation to the necessary intrinsics is left for future implementers of
- https://github.com/llvm/llvm-project/issues/99132
- https://github.com/llvm/llvm-project/issues/156069
- https://github.com/llvm/llvm-project/issues/99131

fixes #156068

- We needed to add a new sub arch to the target tripple so we can test
that emulation does not happen when targeting SM6.9
- The HLSL toolchain needed to be updated to handle the conversion of
strings to enums for the new sub arch.
- The emulation is done in DXILIntrinsicExpansion.cpp and needs to be
able to convert both llvm.is.fpclass and lvm.dx.isinf to the proper
emulation
- test updates in TargetParser/TripleTest.cpp, isinf.ll, is_fpclass.ll,
and DXCModeTest.cpp

Fixes #137209

This PR:
- Adds a case to `expandIntrinsic()` in `DXILIntrinsicExpansion.cpp` to
expand the `Intrinsic::is_fpclass` in the case of
`FPClassTest::fcNegZero`
- Defines the `IsNaN`, `IsFinite`, `IsNormal` DXIL ops in `DXIL.td`
- Adds a case to `lowerIntrinsics()` in `DXILOpLowering.cpp` to handle
the lowering of `Intrinsic::is_fpclass` to the DXIL ops `IsNaN`,
`IsInf`, `IsFinite`, `IsNormal` when the FPClassTest is `fcNan`,
`fcInf`, `fcFinite`, and `fcNormal` respectively
- Creates a test `llvm/test/CodeGen/DirectX/is_fpclass.ll` to exercise
the intrinsic expansion and DXIL op lowering of `Intrinsic::is_fpclass`

~~A separate PR will be made to remove the now-redundant `dx_isinf`
intrinsic to address #87777.~~

A proper implementation for the lowering of the `llvm.is.fpclass`
intrinsic to handle all possible combinations of FPClassTest can be
implemented in a separate PR. This PR's implementation focuses primarily
on addressing the current use-cases for DirectML and HLSL intrinsics.