[3/4] ntdll: Fix up instruction pointer in context for EXCEPTION_BREAKPOINT on x86_64.

[Marvin]

Hi,

While running your changed tests on Windows, 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=20711

Your paranoid android.


=== wvistau64 (32 bit exception) ===
exception.c:490: Test failed: 42: Unexpected eip 0x3c0000/0x3c0001
exception: unhandled exception 80000004 at 003C0000
exception.c:490: Test failed: 42: Unexpected eip 0x77baed97/0x3c0001

=== w7u (32 bit exception) ===
exception.c:490: Test failed: 42: Unexpected eip 0x2f0000/0x2f0001
exception: unhandled exception 80000004 at 002F0000
exception.c:490: Test failed: 42: Unexpected eip 0x77cde34f/0x2f0001

=== w1064 (32 bit exception) ===
Failure running script in VM: network read timed out (Connect:AgentVersion.h:0/9)

=== w1064 (64 bit exception) ===
Failure running script in VM: network read timed out (Connect:AgentVersion.h:0/9)