8305242: Remove non-invariant assert(EventThreadDump::is_enabled())

Reviewed-by: egahlin

Author: Markus Grönlund

src/hotspot/share/jfr/periodic/jfrThreadDumpEvent.cpp

@@ -57,7 +57,6 @@ static bool execute_dcmd(bufferedStream& st, const char* const cmd) {
 
 // caller needs ResourceMark
 const char* JfrDcmdEvent::thread_dump() {
-  assert(EventThreadDump::is_enabled(), "invariant");
   bufferedStream st;
   execute_dcmd(st, "Thread.print");
   return st.as_string();