cpu-exec: invalidate nocache translation if they are interrupted

In this case, QEMU might longjmp out of cpu-exec.c and miss the final
cleanup in cpu_exec_nocache.  Do this manually through a new compile
flag.

Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
