Remove unnecessary line

Author: jsikstro

test/hotspot/jtreg/ProblemList.txt

@@ -188,8 +188,6 @@ vmTestbase/nsk/monitoring/ThreadMXBean/ThreadInfo/Multi/Multi005/TestDescription
 
 vmTestbase/nsk/monitoring/ThreadMXBean/findMonitorDeadlockedThreads/find006/TestDescription.java 8310144 macosx-aarch64
 
-vmTestbase/nsk/monitoring/MemoryPoolMBean/isUsageThresholdExceeded
-
 vmTestbase/nsk/monitoring/MemoryPoolMBean/isUsageThresholdExceeded/isexceeded001/TestDescription.java 8373022 generic-all
 vmTestbase/nsk/monitoring/MemoryPoolMBean/isUsageThresholdExceeded/isexceeded002/TestDescription.java 8373022 generic-all
 vmTestbase/nsk/monitoring/MemoryPoolMBean/isUsageThresholdExceeded/isexceeded003/TestDescription.java 8373022 generic-all