[TESTBUG] nsk/jdb/locals/locals002: fails with "Prompt is not received during ... milliseconds"

This problem has been around for a while. It likely has gone unnoticed because this test also fails due to JDK-8169718. The failure you see in the log is:

Sending command: cont
reply[0]: >
reply[1]: Breakpoint hit: "thread=main", nsk.jdb.locals.locals002.locals002a.allKindsOfVars(), line=84 bci=0
reply[2]: 84 System.out.println("Arguments but no locals"); // locals002.BREAKPOINT_LINE1
reply[3]:
reply[4]: main[1]
Sending command: locals
reply[0]: Method arguments:
reply[1]: boolVar = false
reply[2]: byteVar = 12
reply[3]: charVar = A
reply[4]: shortVar = 327
reply[5]: intVar = 3647
reply[6]: longVar = 65789
reply[7]: floatVar = 4.852
reply[8]: doubleVar = 3.8976
reply[9]: objVar = "objArgString"
reply[10]: arrVar = instance of int[3] (id=698)
reply[11]: Local variables:
reply[12]: main[1]
Sending command: cont
# ERROR: Caught unexpected exception while executing the test: nsk.share.Failure: Prompt is not received during 300200 milliseconds.

The problem is after the last "cont" it never receives the next main[1] prompt and times out waiting for it. I added some debugging code to print out any remaining replies when the timeout happens, and the log then looks like (just starting with the last "cont" above):

Sending command: cont
receiveReply: FAILED
reply[0]: > Argument
reply[1]: Breakpoint hit: s b"thread=main", nsk.jdb.locals.locals002.locals002a.allKindsOfLocals(), line=100 bci=62
reply[2]: ut n100 System.out.println("Locals but no arguments"); // locals002.BREAKPOINT_LINE2
reply[3]:
reply[4]: o lmain[1] ocals

So the next breakpoint was hit, and the main[1] prompt was sent, but there is a bunch of other text interleaved with all lines of the reply. It actually is output from the following line, which is where the previous breakpoint had stopped:

System.out.println("Arguments but no locals");

So when we continue the above is executed and the next breakpoint hit, but the output from the above gets interleaved in the reply. I'm not too certain why this happens since a println is being used. I thought those were sent a full line at a time. Seems like somewhere lines are being processed a character at a time.