fixup! Update and add tests

Author: matheusaaguiar

test/libsolidity/syntaxTests/storageLayoutSpecifier/immutables.sol

@@ -0,0 +1,10 @@
+contract A {
+    address immutable a = 0x0000000000000000000000000000000000000001;
+    uint immutable x = 1;
+}
+
+contract B is A layout at A.a { }
+contract C is A layout at A.x { }
+// ----
+// TypeError 1139: (138-141): The base slot of the storage layout must be a compile-time constant expression.
+// TypeError 1139: (172-175): The base slot of the storage layout must be a compile-time constant expression.