8244495: Some jlink tests crash on Windows after JDK-8237750

Fix of 8237750 changed the loading zip library to on-demand loading, on Windows, jlink/jimage still assume that zip has been loaded already. Fix to load zip on not loaded.

Reviewed-by: kbarrett, mchung, dholmes, dcubed

src/java.base/share/native/libjimage/imageDecompressor.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 2020, Oracle and/or its affiliates. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -61,7 +61,10 @@ static void* findEntry(const char* name) {
 #ifdef WIN32
     HMODULE handle = GetModuleHandle("zip.dll");
     if (handle == NULL) {
-        return NULL;
+      handle = LoadLibrary("zip.dll");
+    }
+    if (handle == NULL) {
+      return NULL;
     }
     addr = (void*) GetProcAddress(handle, name);
     return addr;