test/hotspot/jtreg/gc/metaspace/CompressedClassSpaceSizeInJmapHeap.java fails after JDK-8217612 as below:

CompressedClassSpaceSizeInJmapHeap.stderr.txt
----------------------
Exception in thread "main" java.lang.NumberFormatException: For input string: "18446744073709547520"
        at java.base/java.lang.NumberFormatException.forInputString(NumberFormatException.java:68)
        at java.base/java.lang.Long.parseLong(Long.java:699)
        at java.base/java.lang.Long.parseLong(Long.java:824)
        at jdk.hotspot.agent/sun.jvm.hotspot.tools.HeapSummary.getFlagValue(HeapSummary.java:298)
        at jdk.hotspot.agent/sun.jvm.hotspot.tools.HeapSummary.run(HeapSummary.java:86)
        at jdk.hotspot.agent/sun.jvm.hotspot.tools.JMap.run(JMap.java:115)
        at jdk.hotspot.agent/sun.jvm.hotspot.tools.Tool.startInternal(Tool.java:260)
        at jdk.hotspot.agent/sun.jvm.hotspot.tools.Tool.start(Tool.java:223)
        at jdk.hotspot.agent/sun.jvm.hotspot.tools.Tool.execute(Tool.java:118)
        at jdk.hotspot.agent/sun.jvm.hotspot.tools.JMap.main(JMap.java:176)
        at jdk.hotspot.agent/sun.jvm.hotspot.SALauncher.runJMAP(SALauncher.java:326)
        at jdk.hotspot.agent/sun.jvm.hotspot.SALauncher.main(SALauncher.java:455)
----------------------

JDK-8217612 handles flag value as unsigned if its type is uintx, size_t, or uint64_t. We should use Long::parseUnsignedLong rather than parseLong().