Add workspace-status.cmd for Windows

This is just a wrapper that invokes bash to run
`tools/unix/workspace-status.sh`.

Follow-up to #1059
and #1060

tools/windows/workspace-status.cmd

@@ -0,0 +1,20 @@
+@setlocal enabledelayedexpansion
+@echo off
+
+@rem find git.exe
+for /F "tokens=* USEBACKQ" %%F in (`where git.exe`) do (
+  set "GIT=%%F"
+  break
+)
+
+@rem Git's bash is located at %GITINSTALLDIR%\bin\bash.exe
+@rem Git's git.exe is typically located at %GITINSTALLDIR%\cmd\git.exe or
+@rem %GITINSTALLDIR%\mingw64\bin\git.exe.
+set "_GITEXEDIR=%GIT:\cmd\git.exe=%"
+set "GITEXEDIR=%_GITEXEDIR:\mingw64\bin\git.exe=%"
+set "BASH=%GITEXEDIR%\bin\bash.exe"
+
+@rem Change to the directory of this script (tools/windows) to
+@rem run bash script in (tools/unix).
+cd "%~dp0"
+"%BASH%" -c ../unix/workspace-status.sh