Simplify static instrumentation rules

[purplepig4657]

Redundant rules

Currently, we have several redundant static instrumentation rules: __plsan_lazy_check and __plsan_check_returned_or_stored_value.

This instrumentation handles situations where the reference count of a memory block reaches zero but is soon restored to one.

Although there are no pointers to the memory block, the situation can be regarded as if an invisible pointer points to the memory block (e.g., the returned value is not stored in a specific pointer immediately after the function returns, but it is still reachable.)

Thus, the __plsan_lazy_check and __plsan_check_returned_or_stored_value functions handle this situation.

However, we can eliminate the need for these functions.

Simplification

• Whenever the reference count reaches to zero, a leak report stored. (leak reports are basically overwrited)
• And then, at the end of program, it checks reference counts of all memory blocks, which reference counts are still zero.