gh-108976: Make sure instrumentation line returns the correct opcode when instruction instrumentation is stripped

[gaogaotiantian]

_Py_call_instrumentation_line curently tries to get the original opcode before executing the trace function. The opcode can be INSTRUMENT_INSTRUCTION if instruction event is set. However, the trace function/monitoring callbacks can turn off the instruction event inside the function, which would invalidate the orignal opcode.

line_data->original_opcode won't help in this case as it will still store INSTRUMENT_INSTRUCTION - it won't be refreshed. So, in this case, we use the opcode directly if INSTRUCTION event is turned off on the code object entirely.

• Issue: test_pdb crashes when run after test_sys_settrace #108976