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Avoid out-of-range PC for stack overflow error from snapshot restore.

Reported by Sergey Kaplun.

(cherry picked from commit cd4af8ad8)

When restoring a snapshot because of exiting by the check of the stack,
the snapshot from the parent trace is used. For the correct error
message, the snapshot map uses the next bytecode after the stored one.
In case, when the PC in the snapshot is BC_RET* (the last bytecode in
the prototype), there is no next value to be referenced, so this
approach leads to the assertion failure in `lj_debug_framepc()`.

This patch prevents this behaviour by checking the original bytecode and
avoiding PC adjusting in the case of the last bytecode in the prototype.

Sergey Kaplun:
* added the description and the test for the problem

Part of tarantool/tarantool#11278

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