[PATCH] ntdll: Fix unwinding from leaf function on x86_64.

[Derek Lesho]

I'm not sure why that test fails, that test shouldn't even trigger the
code I change.  By the way, I made a test case that compiles in MSVC.
It's slightly modified from the MSDN's seh example to showcase the
issue with leaf functions: https://godbolt.org/z/mo1-HV

On Fri, Mar 15, 2019 at 3:40 PM Marvin <testbot at winehq.org> wrote:
>
> Hi,
>
> While running your changed tests, I think I found new failures.
> Being a bot and all I'm not very good at pattern recognition, so I might be
> wrong, but could you please double-check?
>
> Full results can be found at:
> https://testbot.winehq.org/JobDetails.pl?Key=49463
>
> Your paranoid android.
>
>
> === debian9b (64 bit WoW report) ===
>
> ntdll:
> env.c:498: Test failed: wrong end ptr 0x1238c/0x12390