Add postfix update expression fixtures.

(Failing.)

packages/babel-plugin-transform-es2015-parameters/test/fixtures/parameters/rest-member-expression-deoptimisation/actual.js

@@ -84,3 +84,11 @@ function arrayDestructure (...rest) {
 function forOf (...rest) {
   for (rest[0] of this);
 }
+
+function postfixIncrement (...rest) {
+  rest[0]++;
+}
+
+function postfixDecrement (...rest) {
+  rest[0]--;
+}

packages/babel-plugin-transform-es2015-parameters/test/fixtures/parameters/rest-member-expression-deoptimisation/expected.js

@@ -178,3 +178,19 @@ function forOf() {
     }
   }
 }
+
+function postfixIncrement() {
+  for (var _len18 = arguments.length, rest = Array(_len18), _key18 = 0; _key18 < _len18; _key18++) {
+    rest[_key18] = arguments[_key18];
+  }
+
+  rest[0]++;
+}
+
+function postfixDecrement() {
+  for (var _len19 = arguments.length, rest = Array(_len19), _key19 = 0; _key19 < _len19; _key19++) {
+    rest[_key19] = arguments[_key19];
+  }
+
+  rest[0]--;
+}