Weekly release v0.2.48: Fuzz tester and join logic refactor

Summary:
Fixes #2151 #2222 #2279 #2393 #2399 #2404 #2411 #2414 #2415
Added a fuzz testing tool
Added test cases
Turn crash in JSON.stringify into a diagnostic
Adds a `arrayNestedOptimizedFunctionsEnabled` flag to enable nested optimized functions derived from Array.prototype methods (like `map`) and Array.from
Refactor assignment on partial or possibly deleted property
Rewrote the joining logic to always do a full join at every join point
Removed last remnants of delayUnsupportedRequires

Reviewed By: cblappert

Differential Revision: D9349841

fbshipit-source-id: 74a16dbb015777d59d23fdfde77abbe2489c292a

package.json

@@ -1,6 +1,6 @@
 {
   "name": "prepack",
-  "version": "0.2.48-alpha.0",
+  "version": "0.2.48",
   "description": "Execute a JS bundle, serialize global state and side effects to a snapshot that can be quickly restored.",
   "homepage": "https://github.com/facebook/prepack",
   "repository": {