[llvm] [DAGCombiner] Fold subtraction if above threshold to `umin` (PR #134235)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `premerge-monolithic-windows` running on `premerge-windows-1` while building `llvm` at step 8 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/35/builds/9030

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 8 (test-build-unified-tree-check-all) failure: test (failure)
...
[25/121] Linking CXX executable tools\clang\tools\extra\unittests\clang-move\ClangMoveTests.exe
[26/121] Linking CXX executable tools\clang\unittests\InstallAPI\InstallAPITests.exe
[27/121] Linking CXX executable tools\clang\tools\extra\unittests\clang-include-fixer\find-all-symbols\FindAllSymbolsTests.exe
[28/121] Linking CXX executable tools\clang\tools\extra\unittests\clang-query\ClangQueryTests.exe
[29/121] Linking CXX executable tools\clang\tools\extra\unittests\clang-change-namespace\ClangChangeNamespaceTests.exe
[30/121] Linking CXX executable tools\polly\unittests\Isl\IslTests.exe
[31/121] Linking CXX executable tools\polly\unittests\Flatten\FlattenTests.exe
[32/121] Linking CXX executable tools\clang\tools\extra\unittests\clang-tidy\ClangTidyTests.exe
[33/121] Linking CXX executable tools\polly\unittests\Support\ISLToolsTests.exe
[34/121] Preparing lit tests
FAILED: utils/lit/CMakeFiles/prepare-check-lit 
cmd.exe /C "cd /D C:\ws\buildbot\premerge-monolithic-windows\build\utils\lit && C:\BuildTools\Common7\IDE\CommonExtensions\Microsoft\CMake\CMake\bin\cmake.exe -E remove_directory C:/ws/buildbot/premerge-monolithic-windows/build/utils/lit/tests && C:\BuildTools\Common7\IDE\CommonExtensions\Microsoft\CMake\CMake\bin\cmake.exe -E copy_directory C:/ws/buildbot/premerge-monolithic-windows/llvm-project/llvm/utils/lit/tests C:/ws/buildbot/premerge-monolithic-windows/build/utils/lit/tests && C:\BuildTools\Common7\IDE\CommonExtensions\Microsoft\CMake\CMake\bin\cmake.exe -E copy C:/ws/buildbot/premerge-monolithic-windows/build/utils/lit/lit.site.cfg C:/ws/buildbot/premerge-monolithic-windows/build/utils/lit/tests"
Error removing directory "C:/ws/buildbot/premerge-monolithic-windows/build/utils/lit/tests".
[35/121] Linking CXX executable tools\clang\unittests\Analysis\ClangAnalysisTests.exe
[36/121] Linking CXX executable bin\mlir-capi-translation-test.exe
[37/121] Linking CXX executable tools\clang\unittests\Analysis\FlowSensitive\ClangAnalysisFlowSensitiveTests.exe
[38/121] Linking CXX executable tools\clang\unittests\ASTMatchers\Dynamic\DynamicASTMatchersTests.exe
[39/121] Linking CXX executable tools\polly\unittests\ScopPassManager\ScopPassManagerTests.exe
[40/121] Linking CXX executable tools\polly\unittests\DeLICM\DeLICMTests.exe
[41/121] Linking CXX executable tools\polly\unittests\ScheduleOptimizer\ScheduleOptimizerTests.exe
[42/121] Linking CXX executable tools\clang\unittests\Rewrite\RewriteTests.exe
[43/121] Linking CXX executable tools\clang\unittests\Sema\SemaTests.exe
[44/121] Linking CXX executable tools\clang\unittests\AST\ByteCode\InterpTests.exe
[45/121] Linking CXX executable tools\clang\unittests\CrossTU\CrossTUTests.exe
[46/121] Linking CXX executable unittests\Analysis\AnalysisTests.exe
[47/121] Linking CXX executable tools\clang\unittests\Support\ClangSupportTests.exe
[48/121] Linking CXX executable tools\clang\unittests\Index\IndexTests.exe
[49/121] Linking CXX executable tools\clang\unittests\Serialization\SerializationTests.exe
[50/121] Linking CXX executable tools\clang\unittests\Tooling\Syntax\SyntaxTests.exe
[51/121] Linking CXX executable tools\mlir\unittests\Target\LLVM\MLIRTargetLLVMTests.exe
[52/121] Linking CXX executable tools\clang\unittests\AST\ASTTests.exe
[53/121] Linking CXX executable tools\clang\unittests\ASTMatchers\ASTMatchersTests.exe
[54/121] Linking CXX executable tools\clang\unittests\StaticAnalyzer\StaticAnalysisTests.exe
[55/121] Linking CXX executable tools\clang\unittests\CodeGen\ClangCodeGenTests.exe
[56/121] Linking CXX executable tools\clang\tools\extra\clangd\unittests\ClangdTests.exe
[57/121] Linking CXX executable tools\clang\unittests\Frontend\FrontendTests.exe
[58/121] Linking CXX executable bin\mlir-capi-pass-test.exe
[59/121] Linking CXX executable bin\mlir-capi-ir-test.exe
[60/121] Linking CXX executable bin\mlir-capi-execution-engine-test.exe
[61/121] Linking CXX executable tools\clang\unittests\Driver\ClangDriverTests.exe
[62/121] Linking CXX executable tools\clang\unittests\Tooling\ToolingTests.exe
[63/121] Linking CXX executable tools\lld\unittests\AsLibELF\LLDAsLibELFTests.exe
[64/121] Linking CXX executable tools\lld\unittests\AsLibAll\LLDAsLibAllTests.exe
[65/121] Linking CXX executable tools\clang\unittests\Interpreter\ClangReplInterpreterTests.exe
ninja: build stopped: subcommand failed.

```

</details>

https://github.com/llvm/llvm-project/pull/134235