[DirectX] Run shader flags analysis before DXILOpLowering

[bogner]

We should run shader flags analysis before DXILOpLowering, so that it can work with DirectX target intrinsics rather than having to recover information from the lowered operations. This will significantly simplify tasks like #118140 and #114557.

Note that this will mean very late passes (ie, DXContainerGlobals) shouldn't rely on shader flags analysis directly, since it won't be possible to re-run it if it's invalid at that point. This is tracked in #120152

To do:

• Move the translate metadata pass after the dxil op lowering pass
• Add asserts if flag analysis is run post lowering