Use FinishThunk to finish musttail thunks
FinishThunk, and the invariant of setting and then unsetting
CurCodeDecl, was added in 7f416cc42638 (2015). The invariant didn't
exist when I added this musttail codepath in ab2090d10765 (2014).
Recently in 28328c3771, I started using this codepath on non-Windows
platforms, and users reported problems during release testing
(PR44987).
The issue was already present for users of EH on i686-windows-msvc,
so I added a test for that case as well.
Reviewed By: hans
Differential Revision: https://reviews.llvm.org/D76444
This should fix 'Assertion failed: (!empty() && "popping exception stack
when not empty"), function popTerminate, file
/usr/src/contrib/llvm-project/clang/lib/CodeGen/CGCleanup.h, line 583'
when building the net-p2p/libtorrent-rasterbar
PR: 244830
Reported by: jbeich, yuri
MFC after: 6 weeks
X-MFC-With: 358851
b362f7400b