improve windows RBE build

tools/internal_ci/windows/bazel_rbe.bat

@@ -12,7 +12,19 @@
 @rem See the License for the specific language governing permissions and
 @rem limitations under the License.
 
-choco install bazel -y --version 0.23.2
+@rem TODO(jtattermusch): make this generate less output
+choco install bazel -y --version 0.23.2 --limit-output
+
 cd github/grpc
-set PATH=%PATH%;C:\python27\
-bazel --bazelrc=tools/remote_build/windows.bazelrc build :all --incompatible_disallow_filetype=false --google_credentials=%KOKORO_GFILE_DIR%/rbe-windows-credentials.json
+set PATH=C:\tools\msys64\usr\bin;C:\Python27;%PATH%
+
+@rem Generate a random UUID and store in "bazel_invocation_ids" artifact file
+powershell -Command "[guid]::NewGuid().ToString()" >%KOKORO_ARTIFACTS_DIR%/bazel_invocation_ids
+set /p BAZEL_INVOCATION_ID=<%KOKORO_ARTIFACTS_DIR%/bazel_invocation_ids
+
+bazel --bazelrc=tools/remote_build/windows.bazelrc build --invocation_id="%BAZEL_INVOCATION_ID%" --workspace_status_command=tools/remote_build/workspace_status_kokoro.sh :all --incompatible_disallow_filetype=false --google_credentials=%KOKORO_GFILE_DIR%/rbe-windows-credentials.json
+set BAZEL_EXITCODE=%errorlevel%
+
+@rem TODO(jtattermusch): upload results to bigquery
+
+exit /b %BAZEL_EXITCODE%