[misc] Downgrade clang version to 14.0.6 on CI (#8417)

Issue: #

### Brief Summary

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Update clang dependency for Windows LLVM backend. This file changes the
download URL for `clang` on Windows to use version 14.0.6, which has bug
fixes and better compatibility for the LLVM backend of the `taichi`
compiler.

### Walkthrough

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* Upgrade the LLVM backend of the taichi compiler by using a newer
version of clang on Windows
([link](https://github.com/taichi-dev/taichi/pull/8417/files?diff=unified&w=0#diff-67455722e4753f6e374de9e8113c60adb89c5e011615abe630a5806c87638ca0L40-R40))

.github/workflows/scripts/ti_build/compiler.py

@@ -25,7 +25,7 @@ def setup_clang(as_compiler=True) -> None:
     """
     u = platform.uname()
     if u.system in ("Linux", "Darwin"):
-        for v in ("", "-15", "-14", "-13", "-12", "-11", "-10"):
+        for v in ("", "-14", "-13", "-12", "-11", "-10"):
             clang = shutil.which(f"clang{v}")
             if clang is not None:
                 clangpp = shutil.which(f"clang++{v}")
@@ -36,8 +36,8 @@ def setup_clang(as_compiler=True) -> None:
             return
 
     elif (u.system, u.machine) == ("Windows", "AMD64"):
-        out = get_cache_home() / "clang-15-v2"
-        url = "https://github.com/taichi-dev/taichi_assets/releases/download/llvm15/clang-15.0.0-win-complete.zip"
+        out = get_cache_home() / "clang-14-v2"
+        url = "https://github.com/taichi-dev/taichi_assets/releases/download/llvm15/clang-14.0.6-win-complete.zip"
         download_dep(url, out, force=True)
         clang = str(out / "bin" / "clang++.exe").replace("\\", "\\\\")
         clangpp = clang

CMakeLists.txt

@@ -197,10 +197,6 @@ if (TI_WITH_LLVM)
 
     check_clang_version()
 
-    if (${CLANG_VERSION_MAJOR} VERSION_GREATER ${CLANG_HIGHEST_VERSION})
-      message(FATAL_ERROR "${CLANG_EXECUTABLE} version: ${CLANG_VERSION}, required: <=${CLANG_HIGHEST_VERSION}. Consider passing -DCLANG_EXECUTABLE=/path/to/clang to cmake to use a specific clang.")
-    endif()
-
     add_subdirectory(taichi/runtime/llvm/runtime_module)
 endif()