fix some bugs in PathHoister - fixes babel-plugins/babel-plugin-react-constant-elements#1

- Don't hoist constant elements to the same function as their original paths function parent.
 - Push each violation paths ancestry to the breakOnScopePaths collection to avoid constant hoisting to nested paths.

test/core/fixtures/transformation/optimisation.react.constant-elements/deep-constant-violation/actual.js

@@ -0,0 +1,9 @@
+function render() {
+  var children = <b></b>;
+
+  if (someCondition) {
+    children = <span></span>;
+  }
+
+  return <div>{children}</div>;
+}

test/core/fixtures/transformation/optimisation.react.constant-elements/deep-constant-violation/expected.js

@@ -0,0 +1,15 @@
+"use strict";
+
+var _ref = <b></b>;
+
+var _ref2 = <span></span>;
+
+function render() {
+  var children = _ref;
+
+  if (someCondition) {
+    children = _ref2;
+  }
+
+  return <div>{children}</div>;
+}

test/core/fixtures/transformation/optimisation.react.constant-elements/dont-hoist-to-same-function/actual.js

@@ -0,0 +1,7 @@
+function renderSome(a, b) {
+  if (a) {
+    return <div>{b}</div>
+  } else {
+    return <span>{b}</span>
+  }
+}

test/core/fixtures/transformation/optimisation.react.constant-elements/dont-hoist-to-same-function/expected.js

@@ -0,0 +1,9 @@
+"use strict";
+
+function renderSome(a, b) {
+  if (a) {
+    return <div>{b}</div>;
+  } else {
+    return <span>{b}</span>;
+  }
+}