tools,win: fix find_python error

On a machine without `python.exe` in the PATH the script was failing
with:

```console
> .\vcbuild.bat
Looking for Python 2.x
2> was unexpected at this time.
```

Escaping the `>` seems to resolve it.

PR-URL: #22797
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>

tools/msvs/find_python.cmd

@@ -26,7 +26,7 @@ EXIT /B
 
 :: Query registry sub-tree for InstallPath
 :find-key
-FOR /F "delims=" %%a IN ('REG QUERY %1 /s 2> NUL ^| findstr "2." ^| findstr InstallPath') DO IF NOT ERRORLEVEL 1 CALL :find-path %%a
+FOR /F "delims=" %%a IN ('REG QUERY %1 /s 2^> NUL ^| findstr "2." ^| findstr InstallPath') DO IF NOT ERRORLEVEL 1 CALL :find-path %%a
 EXIT /B
 
 :: Parse the value of %1 as the path for python.exe