Add Conditionalized Promise Internal Bytecode.

Summary:
This diff add `Promise` to the internal bytecode.

The Promise Internal Bytecode is generated on the fly from the npm
`promise` polyfill package with some refinements so that
- It use the HermesInternal promise rejection tracking configuration.
- Its initialization is conditionalized against
  `HermesInternal.hasPromise()`.

A shell script is introduced in `util` to automate this tedious process.

Reviewed By: avp

Differential Revision: D23486048

fbshipit-source-id: 29a7a1cfcb0a8892939d6a1993810cda538aab9d

lib/InternalBytecode/CMakeLists.txt

@@ -18,7 +18,7 @@ add_hermes_library(hermesInternalBytecode
     InternalBytecode.cpp
 )
 
-set(JS_COMPILER_FLAGS "-O")
+set(JS_COMPILER_FLAGS "-O" "-Wno-undefined-variable")
 
 # Concatenate all JS files into one source file for compilation.
 # This way there is only one RuntimeModule made for them.
@@ -31,6 +31,7 @@ endif()
 
 set(js_lib_sources
   header.js
+  Promise.js
   footer.js
 )