Extract out website changes for REPL.js

Summary:
Release notes: none

Extracted our website changes from commit: 1dbefcbd83

This was done as suggested in 1dbefcbd83 (commitcomment-26606024).
Closes https://github.com/facebook/prepack/pull/1310

Differential Revision: D6655550

Pulled By: trueadm

fbshipit-source-id: b603657a056ee5124bab7fa85ea277a19509268e

website/js/repl.js

@@ -40,15 +40,28 @@ var optionsConfig = [
   {
     type: "choice",
     name: "compatibility",
-    choices: ["browser", "jsc-600-1-4-17", "node-source-maps", "node-cli"],
+    choices: ["browser", "jsc-600-1-4-17", "node-source-maps", "node-cli", "react-mocks"],
     defaultVal: "browser",
     description: "The target environment for Prepack"
   },
+  {
+    type: "boolean",
+    name: "omitInvariants",
+    defaultVal: true,
+    description: "Do not add invariant conditionals that throw on possible runtime errors."
+  },
   {
     type: "boolean",
     name: "reactEnabled",
-    defaultVal: false,
-    description: "Enables experimental support for React features, such as JSX syntax."
+    defaultVal: true,
+    description: "Enables support for React features, such as JSX syntax."
+  },
+  {
+    type: "choice",
+    name: "reactOutput",
+    choices: ["jsx", "create-element"],
+    defaultVal: "jsx",
+    description: "Specifies the serialization output of JSX nodes when React mode is enabled."
   },
 ];