[WebAssembly] Split CFG-sorting into its own pass. NFC.

CFG sorting was already an independent algorithm from block/loop insertion;
this change makes it more convenient to debug.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@296399 91177308-0d34-0410-b5e6-96231b3b80d8
7 files changed