[SMTChecker] Fix ICE on fixed bytes access

test/libsolidity/smtCheckerTests/types/fixed_bytes_access_1.sol

@@ -0,0 +1,9 @@
+pragma experimental SMTChecker;
+contract c {
+	bytes10[6] data2;
+	function test() public view returns (bytes10 r2) {
+		r2 = data2[4][5];
+	}
+}
+// ----
+// Warning 7989: (123-134): Assertion checker does not yet support index accessing fixed bytes.

test/libsolidity/smtCheckerTests/types/fixed_bytes_access_2.sol

@@ -0,0 +1,11 @@
+pragma experimental SMTChecker;
+contract C {
+	function f(bytes calldata x, uint y) external pure {
+		x[8][0];
+		x[8][5%y];
+	}
+}
+// ----
+// Warning 7989: (101-108): Assertion checker does not yet support index accessing fixed bytes.
+// Warning 7989: (112-121): Assertion checker does not yet support index accessing fixed bytes.
+// Warning 3046: (117-120): Division by zero happens here

test/libsolidity/smtCheckerTests/types/fixed_bytes_access_3.sol

@@ -0,0 +1,18 @@
+pragma experimental SMTChecker;
+contract C {
+	bytes16[][] a;
+	function g() internal view returns (bytes16[] storage) {
+		return a[2];
+	}
+	function h() internal view returns (bytes16) {
+		return a[2][2];
+	}
+	function f() external view {
+		g()[3][4];
+		h()[5];
+	}
+}
+// ----
+// Warning 9118: (238-244): Assertion checker does not yet implement this expression.
+// Warning 7989: (238-247): Assertion checker does not yet support index accessing fixed bytes.
+// Warning 7989: (251-257): Assertion checker does not yet support index accessing fixed bytes.