[LLVM-C] Finish exception instruction bindings - Round 2

Summary:
Previous revision caused a leak in the echo test that got caught by the ASAN bots because of missing free of the handlers array and was reverted in r328759.  Resubmitting the patch with that correction.

Add support for cleanupret, catchret, catchpad, cleanuppad and catchswitch and their associated accessors.

Test is modified from SimplifyCFG because it contains many diverse usages of these instructions.

Reviewers: whitequark, deadalnix

Reviewed By: whitequark

Subscribers: llvm-commits, vlad.tsyrklevich

Differential Revision: https://reviews.llvm.org/D45100

llvm-svn: 328883