[WinEH] Pass the catch adjectives to catchpad directly

This avoids building a fake LLVM IR global variable just to ferry an i32
down into LLVM codegen. It also puts a nail in the coffin of using MS
ABI C++ EH with landingpads, since now we'll assert in the lpad code
when flags are present.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@247843 91177308-0d34-0410-b5e6-96231b3b80d8