Add more compat logic for Rest/SpreadElement for 6.x vs 7.x

packages/babel-types/src/index.js

@@ -64,6 +64,14 @@ for (const type in t.VISITOR_KEYS) {
   registerType(type);
 }
 
+// Compat helpers so code for Babel 6.x is more likely to work on Babel 7.x.
+export function isRestProperty(...args) {
+  return t.isRestElement(...args);
+}
+export function isSpreadProperty(...args) {
+  return t.isSpreadElement(...args);
+}
+
 /**
  * Flip `ALIAS_KEYS` for faster access in the reverse direction.
  */