[Sol->Yul] Implementing dynamic array push for arrays of structs.

test/libsolidity/semanticTests/array/push/array_push_nested_from_calldata.sol

@@ -0,0 +1,16 @@
+contract C {
+    uint8 b = 23;
+    uint120[][] s;
+    uint8 a = 17;
+    function f(uint120[] calldata c) public returns(uint120) {
+        s.push(c);
+        assert(s.length == 1);
+        assert(s[0].length == c.length);
+        assert(s[0].length > 0);
+        return s[0][0];
+    }
+}
+// ====
+// compileViaYul: also
+// ----
+// f(uint120[]): 0x20, 3, 1, 2, 3 -> 1

test/libsolidity/semanticTests/array/push/array_push_nested_from_memory.sol

@@ -0,0 +1,19 @@
+contract C {
+    uint8 b = 23;
+    uint120[][] s;
+    uint8 a = 17;
+    function f() public returns(uint120) {
+        delete s;
+        uint120[] memory m = new uint120[](3);
+        m[0] = 1;
+        s.push(m);
+        assert(s.length == 1);
+        assert(s[0].length == m.length);
+        assert(s[0].length > 0);
+        return s[0][0];
+    }
+}
+// ====
+// compileViaYul: also
+// ----
+// f() -> 1

test/libsolidity/semanticTests/array/push/array_push_struct.sol

@@ -18,6 +18,7 @@ contract c {
         return (data[0].a, data[0].b, data[0].c[2], data[0].d[2]);
     }
 }
-
+// ====
+// compileViaYul: also
 // ----
 // test() -> 2, 3, 4, 5

test/libsolidity/semanticTests/array/push/array_push_struct_from_calldata.sol

@@ -0,0 +1,20 @@
+pragma abicoder v2;
+
+contract c {
+    struct S {
+        uint16 a;
+        uint16 b;
+        uint16[3] c;
+        uint16[] d;
+    }
+    S[] data;
+
+    function test(S calldata c) public returns (uint16, uint16, uint16, uint16) {
+        data.push(c);
+        return (data[0].a, data[0].b, data[0].c[2], data[0].d[2]);
+    }
+}
+// ====
+// compileViaYul: also
+// ----
+// test((uint16, uint16, uint16[3], uint16[])): 0x20, 2, 3, 0, 0, 4, 0xC0, 4, 0, 0, 5, 0, 0 -> 2, 3, 4, 5