devops: support build on macOS 11 (#12742)

browser_patches/checkout_build_archive_upload.sh

@@ -296,6 +296,11 @@ elif [[ "$BUILD_FLAVOR" == "webkit-mac-12-arm64" ]]; then
   EXPECTED_HOST_OS_VERSION="12.2"
   EXPECTED_ARCH="arm64"
   BUILD_BLOB_NAME="webkit-mac-12-arm64.zip"
+elif [[ "$BUILD_FLAVOR" == "webkit-mac-11" ]]; then
+  BROWSER_NAME="webkit"
+  EXPECTED_HOST_OS="Darwin"
+  EXPECTED_HOST_OS_VERSION="11.6"
+  BUILD_BLOB_NAME="webkit-mac-11.zip"
 elif [[ "$BUILD_FLAVOR" == "webkit-mac-11-arm64" ]]; then
   BROWSER_NAME="webkit"
   EXPECTED_HOST_OS="Darwin"