[WinEH] Fix ESP management with 32-bit __CxxFrameHandler3

[WinEH] Fix ESP management with 32-bit __CxxFrameHandler3

The C++ EH personality automatically restores ESP from the C++ EH
registration node after a catchret. I mistakenly thought it was like
SEH, which does not restore ESP.

It makes sense for C++ EH to differ from SEH here because SEH does not
use funclets for catches, and does not allow catching inside of finally.
C++ EH may need to unwind through multiple catch funclets and eventually
catchret to some outer funclet. Therefore, the runtime has to keep track
of which ESP to use with catchret, rather than having the compiler
reload it manually.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253084 91177308-0d34-0410-b5e6-96231b3b80d8