Update .gitignore (WebKit#121)

- Globally exclude node_modules by default
- Ignore v8.log profiling files

Author: camillobruni

.gitignore

@@ -1,7 +1,10 @@
 .DS_Store
 .directory
-/node_modules
+node_modules
 
 # Ignore auto-generated files by VS & VSCode.
 /.vs/
 /.vscode/
+
+# v8.log is generated by the d8-shell if profiling is enabled
+v8.log