tools: call close() explicitly in genv8constants.py

PR-URL: #36606
Reviewed-By: Antoine du Hamel <[email protected]>
Reviewed-By: Luigi Pinca <[email protected]>

Author: Trott

Diff for: tools/genv8constants.py

@@ -113,3 +113,5 @@ def out_define():
 
 #endif /* V8_CONSTANTS_H */
 """)
+
+outfile.close()