Build: Don't save temporary npm dependencies to package.json

Past npm versions required the `--save` flag to save anything in `package.json`
when installing packages but newer ones do this by default. Pass `--no-save` to
restore the original behavior in the `release-test.js` script.

Ref gh-1966

Author: mgol

build/release-test.js

@@ -37,7 +37,7 @@ script( Release );
 
 // Ignores actual version installed, should be good enough for a test
 if ( shell.exec( "npm ls --depth 0 | grep download.jqueryui.com" ).code === 1 ) {
-	shell.exec( "npm install " + script.dependencies.join( " " ) );
+	shell.exec( "npm install --no-save " + script.dependencies.join( " " ) );
 }
 
 // If AUTHORS.txt is outdated, this will update it