This hack was introduced in issue#287 which later becomes endless maintainance pain.
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Our previous check_exit_request use `brcond` in the middle of a TranslationBlock which
breaks the assumptions and thus a hack to liveness_pass_1 is used for _all_ brcond instructions
which causes issues for MIPS and many other scenarios.
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This patch also resolves PC not sync-ed when no memory hooks are installed, finally. Now
Unicorn will always have correct PC no matter what happens.
Consider this case:
t:inc ecx,
inc edx,
jmp t
It would generate exactly one block and TB chain will generate an inline
jump. If we don't check exit at the entry of the block, we will never be
terminated.
This test case is recorded in the commit message since it's a bit
painful to write multithread related code that builds on all platforms.
