Organizing array tests into more directories.

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

@@ -0,0 +1,20 @@
+contract c {
+    uint256[] data;
+
+    function test()
+        public
+        returns (uint256 x, uint256 y, uint256 z, uint256 l)
+    {
+        data.push(5);
+        x = data[0];
+        data.push(4);
+        y = data[1];
+        data.push(3);
+        l = data.length;
+        z = data[2];
+    }
+}
+// ====
+// compileViaYul: also
+// ----
+// test() -> 5, 4, 3, 3