Add class properties test with a generator method that results in a parse error

packages/babylon/test/fixtures/experimental/class-properties/asi-failure-generator/actual.js

@@ -0,0 +1,4 @@
+class Foo {
+  p = x
+  *m () {}
+}

packages/babylon/test/fixtures/experimental/class-properties/asi-failure-generator/options.json

@@ -0,0 +1,4 @@
+{
+  "throws": "Unexpected token (3:8)",
+  "plugins": ["classProperties"]
+}