Organizing array tests into more directories.

test/libsolidity/semanticTests/array/pop/array_pop_empty_exception.sol

@@ -0,0 +1,12 @@
+contract c {
+    uint256[] data;
+
+    function test() public returns (bool) {
+        data.pop();
+        return true;
+    }
+}
+// ====
+// compileViaYul: also
+// ----
+// test() -> FAILURE