standardize pattern conversion

test/basic/package_pattern.sv

@@ -0,0 +1,16 @@
+package PKG;
+    typedef struct packed {
+        logic f;
+    } foo_t;
+endpackage
+
+module top;
+    typedef struct packed {
+        PKG::foo_t f;
+    } local_t;
+    local_t w[0:1];
+    initial begin
+        w <= '{default: 0};
+        $display("%b", w);
+    end
+endmodule