[WebAssembly] Add an assert to sanity-check dead flags.

The WebAssemblyStoreResults pass runs before LiveVariables, so it doesn't
expect to have to keep dead flags up to date; check this with an assert.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@255551 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed