REGRESSION(267608@main): [Win] build-webkit is failing with "'python3…

…' is not recognized as an internal or external command"

https://bugs.webkit.org/show_bug.cgi?id=261183

Reviewed by Ross Kirsling.

Windows Python 3 is python.exe, not python3.exe.

* Tools/Scripts/build-webkit:
Use python to execute update-webkit-wincairo-libs.py instead of python3.

Canonical link: https://commits.webkit.org/267662@main

Tools/Scripts/build-webkit

@@ -288,7 +288,7 @@ if (isAppleCocoaWebKit()) {
     }
 
 } elsif (isWinCairo() && !$skipLibraryUpdate) {
-    (system("python3 Tools/Scripts/update-webkit-wincairo-libs.py") == 0) or die;
+    (system("python Tools/Scripts/update-webkit-wincairo-libs.py") == 0) or die;
 }
 
 # If asked to build just the WebKit project, overwrite the projects