Fix off-by-one error in bounds checks

[mrexodia]

Code snippet to reproduce the bug:

        seg: MinidumpMemorySegment
        for seg in self._minidump.memory_segments_64.memory_segments:
            print(f"initialize base: 0x{seg.start_virtual_address:x}, size: 0x{seg.size:x}")
            self._memory.move(seg.start_virtual_address)
            assert self._memory.current_position == seg.start_virtual_address
            data = self._memory.read(seg.size)

The bounds check first moves the position and then checks if it's in bounds, but this is incorrect because if you read the full page it would look like things are out of bounds even though they aren't.

[mrexodia]

Ping, would be appreciated if this could be merged.