[SMTChecker] Adding test witnessing that SMTChecker no longer crashes when producing CEX with arrays

test/libsolidity/smtCheckerTests/overflow/overflow_mul_cex_with_array.sol

@@ -0,0 +1,10 @@
+pragma experimental SMTChecker;
+
+contract C {
+	function f(bytes calldata x, uint y) external pure {
+		x[8][0];
+		x[8][5*y];
+	}
+}
+// ----
+// Warning 4984: (118-121): CHC: Overflow (resulting value larger than 2**256 - 1) happens here.