Use https over git protocol (#683)

https is the preferred protocol for cloning repos. This switches the
test262 reference to the https protocol.

Author: ewalk153

.gitmodules

@@ -3,4 +3,4 @@
 	url = https://github.com/web-platform-tests/wpt
 [submodule "crates/javy/test262"]
 	path = crates/javy/test262
-	url = git@github.com:tc39/test262.git
+	url = https://github.com/tc39/test262