Until now, if we examined an EPT fault and the corresponding guest
physical memory was not allocated, we forwarded the faulting instruction
to the instruction emulator, which in turn handled the memory allocation
implicitly. This lead to long instruction emulation times on certain
instructions (e.g. 'rep mov' on large memory junks). Therefore, we now
allocate and map the corresponding guest physical memory immediately in
the EPT fault handler and directly return to the guest.
fixes#2645
The main feature for this version upgrade is the use of the instruction
emulator (IEM) to speed up execution and less often the slow recompiler.
issue #2059
