Implement MLIR enablement heuristic

[krzysz00]

Per discussion with @pfultz2 , rocMLIR-based kernel generation will be enabled in the 6.0 release in the following circumstances:

• Any convolution fusion
• Any i8 gemm fusion
• All Navi3x standalone convolutions
• With a flag that is off by default, fp* gemm fusions

Except:

• 3x3 winnograd convolutions fusions (except on Navi)
• K > 2048 on gemm (as for CK)
  • This should be K relative to G * M * N, but if that can't be implemented by release, we'll go for the simple filter

#2274 implements part of this heuristic, but is incomplete (and, for example, doesn't have the "don't skip winnogradable convolutions on Navi" part)

@causten @jerryyin for awareness
If someone could at in Andy (I think) who has the performance measurements scripts for more comments, that'd be helpful