[WebAssembly] Remove unnecessary instructions after TRY marker placement
Summary:
This removes unnecessary instructions after TRY marker placement. There
are two cases:
- `end`/`end_block` can be removed if they overlap with `try`/`end_try`
and they have the same return types.
- `br` right before `catch` that branches to after `end_try` can be
deleted.
Reviewers: dschuff
Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D58591
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@354939
91177308-0d34-0410-b5e6-
96231b3b80d8