build: remove MSVC from Windows Bazel build actions

.github/actions/setup-bazel-ci/action.yml

@@ -59,64 +59,7 @@ runs:
         "BAZEL_OUTPUT_USER_ROOT=$bazelOutputUserRoot" | Out-File -FilePath $env:GITHUB_ENV -Encoding utf8 -Append
         "BAZEL_REPO_CONTENTS_CACHE=$repoContentsCache" | Out-File -FilePath $env:GITHUB_ENV -Encoding utf8 -Append
 
-    - name: Expose MSVC SDK environment (Windows)
-      if: runner.os == 'Windows'
-      shell: pwsh
-      run: |
-        # Bazel exec-side Rust build scripts do not reliably inherit the MSVC developer
-        # shell on GitHub-hosted Windows runners, so discover the latest VS install and
-        # ask `VsDevCmd.bat` to materialize the x64/x64 compiler + SDK environment.
-        $vswhere = "${env:ProgramFiles(x86)}\Microsoft Visual Studio\Installer\vswhere.exe"
-        if (-not (Test-Path $vswhere)) {
-          throw "vswhere.exe not found"
-        }
-
-        $installPath = & $vswhere -latest -products * -requires Microsoft.VisualStudio.Component.VC.Tools.x86.x64 -property installationPath 2>$null
-        if (-not $installPath) {
-          throw "Could not locate a Visual Studio installation with VC tools"
-        }
-
-        $vsDevCmd = Join-Path $installPath 'Common7\Tools\VsDevCmd.bat'
-        if (-not (Test-Path $vsDevCmd)) {
-          throw "VsDevCmd.bat not found at $vsDevCmd"
-        }
-
-        # Keep the export surface explicit: these are the paths and SDK roots that the
-        # MSVC toolchain probes need later when Bazel runs Windows exec-platform build
-        # scripts such as `aws-lc-sys`.
-        $varsToExport = @(
-          'INCLUDE',
-          'LIB',
-          'LIBPATH',
-          'PATH',
-          'UCRTVersion',
-          'UniversalCRTSdkDir',
-          'VCINSTALLDIR',
-          'VCToolsInstallDir',
-          'WindowsLibPath',
-          'WindowsSdkBinPath',
-          'WindowsSdkDir',
-          'WindowsSDKLibVersion',
-          'WindowsSDKVersion'
-        )
-
-        # `VsDevCmd.bat` is a batch file, so invoke it under `cmd.exe`, suppress its
-        # banner, then dump the resulting environment with `set`. Re-export only the
-        # approved keys into `GITHUB_ENV` so later steps inherit the same MSVC context.
-        $envLines = & cmd.exe /c ('"{0}" -no_logo -arch=x64 -host_arch=x64 >nul && set' -f $vsDevCmd)
-        foreach ($line in $envLines) {
-          if ($line -notmatch '^(.*?)=(.*)$') {
-            continue
-          }
-
-          $name = $matches[1]
-          $value = $matches[2]
-          if ($varsToExport -contains $name) {
-            "$name=$value" | Out-File -FilePath $env:GITHUB_ENV -Encoding utf8 -Append
-          }
-        }
-
-    - name: Compute cache-stable Windows Bazel PATH
+    - name: Configure frozen Windows Bazel paths
       if: runner.os == 'Windows'
       shell: pwsh
       run: ./.github/scripts/compute-bazel-windows-path.ps1