[clang] [Win/X86] Make _m_prefetch[w] builtins to avoid winnt.h conflicts (PR #115099)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `flang-aarch64-libcxx` running on `linaro-flang-aarch64-libcxx` while building `clang` at step 5 "build-unified-tree".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/89/builds/15828

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

```
Step 5 (build-unified-tree) failure: build (failure)
...
5.328 [6737/65/521] Building riscv_sifive_vector_builtins.inc...
5.328 [6737/64/522] Building riscv_sifive_vector_builtin_cg.inc...
5.329 [6737/63/523] Building riscv_sifive_vector_builtin_sema.inc...
5.329 [6737/62/524] Building Nodes.inc...
5.329 [6737/61/525] Linking CXX shared library lib/libLLVMCodeGenTypes.so.21.0git
5.330 [6737/60/526] Building DiagnosticInstallAPIKinds.inc...
5.330 [6737/59/527] Building DiagnosticInstallAPIEnums.inc...
5.330 [6737/58/528] Building DiagnosticLexEnums.inc...
5.330 [6737/57/529] Building DiagnosticGroups.inc...
5.331 [6737/56/530] Building BuiltinsX86.inc...
FAILED: tools/clang/include/clang/Basic/BuiltinsX86.inc /home/tcwg-buildbot/worker/flang-aarch64-libcxx/build/tools/clang/include/clang/Basic/BuiltinsX86.inc 
cd /home/tcwg-buildbot/worker/flang-aarch64-libcxx/build && /home/tcwg-buildbot/worker/flang-aarch64-libcxx/build/bin/clang-tblgen -gen-clang-builtins -I /home/tcwg-buildbot/worker/flang-aarch64-libcxx/llvm-project/clang/include/clang/Basic -I/home/tcwg-buildbot/worker/flang-aarch64-libcxx/llvm-project/clang/include -I/home/tcwg-buildbot/worker/flang-aarch64-libcxx/build/tools/clang/include -I/home/tcwg-buildbot/worker/flang-aarch64-libcxx/build/include -I/home/tcwg-buildbot/worker/flang-aarch64-libcxx/llvm-project/llvm/include /home/tcwg-buildbot/worker/flang-aarch64-libcxx/llvm-project/clang/include/clang/Basic/BuiltinsX86.td --write-if-changed -o tools/clang/include/clang/Basic/BuiltinsX86.inc -d tools/clang/include/clang/Basic/BuiltinsX86.inc.d
/home/tcwg-buildbot/worker/flang-aarch64-libcxx/llvm-project/clang/include/clang/Basic/BuiltinsX86.td:147:7: error: Unexpected header name
  def _m_prefetch : X86LibBuiltin<"void(void *)">;
      ^
5.331 [6737/55/531] Building arm_mve_builtins.inc...
5.331 [6737/54/532] Building AttrParserStringSwitches.inc...
5.331 [6737/53/533] Building AttrSubMatchRulesParserStringSwitches.inc...
5.331 [6737/52/534] Building AttrTemplateInstantiate.inc...
5.331 [6737/51/535] Building AttrParsedAttrKinds.inc...
5.331 [6737/50/536] Building AttrPCHRead.inc...
5.331 [6737/49/537] Building Checkers.inc...
5.331 [6737/48/538] Building NodeClasses.inc...
5.331 [6737/47/539] Building arm_fp16.h...
5.331 [6737/46/540] Building arm_sme.h...
5.331 [6737/45/541] Building arm_bf16.h...
5.332 [6737/44/542] Building DiagnosticLexKinds.inc...
5.332 [6737/43/543] Building AttrSpellingListIndex.inc...
5.332 [6737/42/544] Building arm_cde.h...
5.333 [6737/41/545] Building DiagnosticIndexName.inc...
5.334 [6737/40/546] Building DiagnosticRefactoringEnums.inc...
5.334 [6737/39/547] Building DiagnosticParseEnums.inc...
5.334 [6737/38/548] Building arm_vector_types.h...
5.337 [6737/37/549] Building DiagnosticSerializationEnums.inc...
5.338 [6737/36/550] Building AttrPCHWrite.inc...
5.338 [6737/35/551] Building DiagnosticParseKinds.inc...
5.339 [6737/34/552] Building DiagnosticRefactoringKinds.inc...
5.341 [6737/33/553] Building DiagnosticSemaEnums.inc...
5.343 [6737/32/554] Building DiagnosticSerializationKinds.inc...
5.345 [6737/31/555] Building AttrParsedAttrImpl.inc...
5.355 [6737/30/556] Building DiagnosticSemaKinds.inc...
5.359 [6737/29/557] Building arm_mve_builtin_cg.inc...
5.359 [6737/28/558] Building arm_mve.h...
5.383 [6737/27/559] Building IntrinsicsLoongArch.h...
5.386 [6737/26/560] Building arm_sve.h...
5.387 [6737/25/561] Linking CXX shared library lib/libLLVMFrontendOpenACC.so.21.0git
5.390 [6737/24/562] Building IntrinsicsBPF.h...
5.393 [6737/23/563] Building IntrinsicsHexagon.h...
5.393 [6737/22/564] Building IntrinsicEnums.inc...

```

</details>

https://github.com/llvm/llvm-project/pull/115099