OperatingSystemMXBean/TestTotalSwap.java reports wrong swap size in container environment

when com/sun/management/OperatingSystemMXBean/TestTotalSwap.java is run within a docker container, it reproducibly fails:

----------System.out:(10/576)----------
Command line: [free -b]
[2020-10-22T17:12:17.167587967Z] Gathering output for process 1127
[2020-10-22T17:12:17.232271641Z] Waiting for completion for process 1127
[2020-10-22T17:12:17.232502672Z] Waiting for completion finished for process 1127
Output and diagnostic info for process 1127 was saved into 'pid-1127-output.log'
              total used free shared buff/cache available
Mem: 63037734912 2755280896 31014617088 67817472 29267836928 58851241984
Swap: 8589930496 798720 8589131776

Total swap space size in bytes: 61963501568
----------System.err:(12/778)----------
java.lang.RuntimeException: Expected total swap size : 8589930496 but getTotalSwapSpaceSize returned: 61963501568
at TestTotalSwap.main(TestTotalSwap.java:92)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:64)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at com.sun.javatest.regtest.agent.MainActionHelper$AgentVMRunnable.run(MainActionHelper.java:298)
at java.base/java.lang.Thread.run(Thread.java:832)