[WinEH] Put funclet bundles on inline asm calls

Summary:
Fixes PR36247, which is where WinEHPrepare replaces inline asm in
funclets with unreachable.

Make getBundlesForFunclet return by value to simplify some call sites.

Reviewers: smeenai, majnemer

Subscribers: eraman, cfe-commits

Differential Revision: https://reviews.llvm.org/D43033

llvm-svn: 324689