[WinEH] Reusing HandlerType entries leads to small CatchHigh values

CatchHigh may be smaller than TryHigh if we reuse an outlined catch
handler for two different invokes with different EH states.  We have no
evidence which shows that CatchHigh must be greater than TryHigh or
TryLow.  We can revisit this if we turn out to be wrong.

llvm-svn: 235223