gh-150587: Harden BINARY_OP_SUBSCR_LIST_INT/STORE_SUBSCR_LIST_INT against non-compact int subscripts

[KRRT7]

Add EXIT_IF(!_PyLong_IsNonNegativeCompact(...)) to _BINARY_OP_SUBSCR_LIST_INT and DEOPT_IF(!_PyLong_IsNonNegativeCompact(...)) to _STORE_SUBSCR_LIST_INT before the _PyLong_CompactValue call.

Both opcodes currently rely on _GUARD_TOS_INT having already rejected non-compact ints, but do not enforce this themselves. If _GUARD_TOS_INT were relaxed, _PyLong_CompactValue would be called on a wide int, silently reading ob_digit[0] as the index instead of the full value.

Fixes gh-150587.

[bedevere-app]

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[KRRT7]

closing as per #150587 (comment):

my work on 150425 is what triggers this bug, and is why I had opened this issue. after a chat with @ZeroIntensity I'm moving the patch into 150425