[Sol->Yul] Implement getters.

test/libsolidity/semanticTests/getters/arrays.sol

@@ -0,0 +1,14 @@
+contract C {
+    uint8[][2] public a;
+    constructor() public {
+        a[1].push(3);
+        a[1].push(4);
+    }
+}
+// ====
+// compileViaYul: also
+// ----
+// a(uint256,uint256): 0, 0 -> FAILURE
+// a(uint256,uint256): 1, 0 -> 3
+// a(uint256,uint256): 1, 1 -> 4
+// a(uint256,uint256): 2, 0 -> FAILURE

test/libsolidity/semanticTests/getters/mapping.sol

@@ -0,0 +1,11 @@
+contract C {
+    mapping(uint => mapping(uint => uint)) public x;
+    constructor() public {
+        x[1][2] = 3;
+    }
+}
+// ====
+// compileViaYul: also
+// ----
+// x(uint256,uint256): 1, 2 -> 3
+// x(uint256,uint256): 0, 0 -> 0

test/libsolidity/semanticTests/getters/small_types.sol

@@ -0,0 +1,19 @@
+contract C {
+    uint8 public a;
+    uint16 public b;
+    uint128 public c;
+    uint public d;
+    constructor() public {
+        a = 3;
+        b = 4;
+        c = 5;
+        d = 6;
+    }
+}
+// ====
+// compileViaYul: also
+// ----
+// a() -> 3
+// b() -> 4
+// c() -> 5
+// d() -> 6

test/libsolidity/semanticTests/storage/accessors_mapping_for_array.sol

@@ -8,6 +8,8 @@ contract test {
         dynamicData[2][2] = 8;
     }
 }
+// ====
+// compileViaYul: also
 // ----
 // data(uint256,uint256): 2, 2 -> 8
 // data(uint256,uint256): 2, 8 -> FAILURE  # NB: the original code contained a bug here #