Unknown bug with `CHECK-NOT`:

[AntonLydike]

When running against upstream LLVM/MLIR tests, I see a bunch of very similar failures, which I suspect are due to the same bug. I am not quite sure what's wrong yet though.

Currently responsible for 22 / 69 remaining test failures:

• mlir/test/Conversion/GPUCommon/lower-memcpy-to-gpu-runtime-calls.mlir:10
• mlir/test/Dialect/Affine/loop-fusion-3.mlir
• mlir/test/mlir-tblgen/op-format.mlir
• mlir/test/Target/LLVMIR/test.mlir:9
• mlir/test/Rewrite/pdl-bytecode.mlir:66
• mlir/test/Dialect/LLVMIR/inlining.mlir:483
• mlir/test/Target/LLVMIR/Import/debug-info.ll:614
• mlir/test/Dialect/GPU/async-region.mlir:176
• mlir/test/Dialect/LLVMIR/mem2reg-dbginfo.mlir:118
• mlir/test/Dialect/Affine/SuperVectorize/vector_utils.mlir:24
• mlir/test/Conversion/FuncToLLVM/emit-c-wrappers-for-external-callers.mlir:5
• mlir/test/Dialect/LLVMIR/sroa-intrinsics.mlir:194
• mlir/test/Dialect/Linalg/one-shot-bufferize.mlir:74
• mlir/test/Dialect/LLVMIR/inlining-alias-scopes.mlir:140
• mlir/test/Dialect/MemRef/sroa.mlir:8
• mlir/test/Dialect/LLVMIR/mem2reg.mlir:264
• mlir/test/Conversion/FuncToLLVM/emit-c-wrappers-for-external-functions.mlir:6
• mlir/test/IR/module-op.mlir:31
• mlir/test/CAPI/llvm.c:300
• mlir/test/Dialect/Linalg/subtensor-of-padtensor.mlir:116
• mlir/test/Dialect/Affine/unroll.mlir:424
• mlir/test/Dialect/SCF/wrap-while-loop-in-zero-trip-check.mlir:111