RFR: 8139564: Convert TraceDefaultMethods to Unified Logging

[Rachel Protacio]

Hello! Please take a look at my enhancement, the first of the runtime 
logging flags to be converted.

Summary: The former -XX:+TraceDefaultMethods flag is updated to the 
unified logging framework and is now replaced with -Xlog:defaultmethods.

open webrev: http://cr.openjdk.java.net/~rprotacio/8139564/
bug: https://bugs.openjdk.java.net/browse/JDK-8139564
testing: Passes JPRT, RBT, and RefWorkload performance testing.

Thank you,
Rachel