move all plugin tests out of babel-core and into their appropriate folders

packages/babel-plugin-transform-react-inline-elements/test/fixtures/inline-elements/children-exists/actual.js

@@ -0,0 +1 @@
+<div children="foo">bar</div>;

packages/babel-plugin-transform-react-inline-elements/test/fixtures/inline-elements/children-exists/expected.js

@@ -0,0 +1,11 @@
+({
+  $$typeof: babelHelpers.typeofReactElement,
+  type: "div",
+  key: null,
+  ref: null,
+  props: {
+    children: "foo",
+    children: "bar"
+  },
+  _owner: null
+});