[SMTChecker] Support delete

test/libsolidity/smtCheckerTests/operators/delete_array.sol

@@ -0,0 +1,21 @@
+pragma experimental SMTChecker;
+
+contract C
+{
+	uint[] a;
+	function f(bool b) public {
+		a[2] = 3;
+		require(b);
+		if (b)
+			delete a;
+		else
+			delete a[2];
+		// Assertion fails as false positive because
+		// setZeroValue for arrays needs \forall i . a[i] = 0
+		// which is still unimplemented.
+		assert(a[2] == 0);
+	}
+}
+// ----
+// Warning: (118-119): Condition is always true.
+// Warning: (297-314): Assertion violation happens here