[CMake] [MLIR] [Backport] Backport cmake from upstream to add missing mlir-headers dependencies

[badumbatish]

Similar to #1927 , this allows generation of the missing mlir tablegen targets without going through

$(ninja -C build_pilot -t targets all | grep IncGen | sed 's/:.*//')

Helpful to #1917

[badumbatish]

hmm not quite sure why its failing flang test cases due to error: unknown argument: '-emit-mlir'

[badumbatish]

hmm not quite sure why its failing flang test cases due to error: unknown argument: '-emit-mlir'

it seems this is a problem from upstream, I run the build command on check-flang against HEAD~1 and it fails with the same error msg

[bcardosolopes]

it seems this is a problem from upstream, I run the build command on check-flang against HEAD~1 and it fails with the same error msg

We don't run check-flang in this CI (we're supposed to only run check-clang-cir) - see previous green jobs and look at the output - so maybe some of the cmake changes here are triggering dependencies it shouldn't?