Add test coverage for deque::erase(iter, iter) avoiding self-move-assigns

[StephanTLavavej]

#1118 was fixed by #1148, so deque::erase(iter, iter) avoids performing self-move-assigns when called with empty ranges. We should have test coverage for this scenario. Our test for vector can be extended:

STL/tests/std/tests/Dev10_881629_vector_erase_return_value/test.cpp

Lines 10 to 11 in 1913566

	// Also test DevCom-776568 "vector::erase(a, a) self-move-assigns the whole vector"
	struct CheckSelfMoveAssign {