objdump: Support newer ObjC image info flags

Summary:
Add support for two additional ObjC image info flags: `IS_SIMULATED` and
`HAS_CATEGORY_CLASS_PROPERTIES`.

`IS_SIMULATED` indicates a Mach-O binary built for iOS simulator.

`HAS_CATEGORY_CLASS_PROPERTIES` indicates a Mach-O binary built by a compiler
that supports class properties in categories.

Reviewers: enderby, compnerd

Reviewed By: compnerd

Subscribers: keith, llvm-commits

Differential Revision: https://reviews.llvm.org/D48568

llvm-svn: 336399