RFR(XS): 8159901: missing newline char in the exception messages in diagnosticArgument.cpp

[Calvin Cheung]

Please review this small fix for adding the missing newline char in the 
exception messages in diagnosticArgument.cpp.

If the vm_exit_during_initialization() is called after the THROW_MSG() 
in diagnosticArgument.cpp, the error looks like the following:
java.lang.IllegalArgumentException: Integer parsing error nanotime 
value: syntax errorError occurred during initialization of VM
Failed to start tracing backend.

After the fix, it becomes:
java.lang.IllegalArgumentException: Integer parsing error nanotime 
value: syntax error
Error occurred during initialization of VM
Failed to start tracing backend.

bug: https://bugs.openjdk.java.net/browse/JDK-8159901
         (it is marked confidential)

webrev: http://cr.openjdk.java.net/~ccheung/8159901/webrev.00/

The fix passed JPRT and related tests in the closed repo.

thanks,
Calvin