Update LLVM to llvm/llvm-project@cea738bc

[raikonenfnu]

Update LLVM to llvm/llvm-project@b13592219c421820b (llvm/llvm-project#85376) Changes done to resolve mlirbc issue in #19498 through updating/regen of input IRs in azure and SHARK-TestSuite to work with latest mlir-opt.

This PR also carries the following reverts:

llvm/llvm-project#120999
llvm/llvm-project#120115
llvm/llvm-project#119461

The main issue with this PR(12099 and 120115) is it breaks matvec codegen generating scf.if instead of scf.for(s). An issue will be pushed up for repro.

The main issue with PR 119461 is it breaks e2e riscv test by making it get stuck on infinite loop.

/path/to/iree-build/tools/iree-compile --output-format=vm-bytecode --mlir-print-op-on-diagnostic=false --iree-hal-target-backends=llvm-cpu --iree-input-type=stablehlo --iree-input-demote-f64-to-f32 --iree-llvmcpu-target-cpu=generic /path/to/iree/tests/e2e/stablehlo_ops/three_fry.mlir -o three_fly_exec_target.mlir --iree-llvmcpu-target-triple=riscv64 --iree-llvmcpu-target-abi=lp64d --iree-llvmcpu-target-cpu-features=+m,+a,+d,+zvl512b,+v --mlir-disable-threading
> infinite loop

[ScottTodd]

Do you still want this PR? Looks like similar changes in #19554.

[raikonenfnu]

@ScottTodd Yes you are right, I'm going to close it now. Thanks for checking on this. :)