build,win: fix Python detection on localized OS

This code previously assumed the default value was always printed to
the console by reg.exe as "(default)", but this is not true on
localized versions of Windows and can contain spaces.

Fixes: #29417

Author: joaocgreis

tools/msvs/find_python.cmd

@@ -60,14 +60,16 @@ exit /b 1
 :: Read the InstallPath of a given Environment Key to %p%
 :: https://www.python.org/dev/peps/pep-0514/#installpath
 :read-installpath
-:: %%a will receive token 3
-:: %%b will receive *, corresponding to token 4 and all after
-for /f "skip=2 tokens=3*" %%a in ('reg query "%1\InstallPath" /ve /t REG_SZ 2^> nul') do (
-  set "head=%%a"
-  set "tail=%%b"
-  set "p=!head!"
-  if not "!tail!"=="" set "p=!head! !tail!"
-  exit /b 0
+:: %%a will receive everything before ), might have spaces depending on language
+:: %%b will receive *, corresponding to everything after )
+:: %%c will receive REG_SZ
+:: %%d will receive the path, including spaces
+for /f "skip=2 tokens=1* delims=)" %%a in ('reg query "%1\InstallPath" /ve /t REG_SZ 2^> nul') do (
+  for /f "tokens=1*" %%c in ("%%b") do (
+    if not "%%c"=="REG_SZ" exit /b 1
+    set "p=%%d"
+    exit /b 0
+  )
 )
 exit /b 1