RFR: JDK-8230519: jpackage "--package-type" values and default

Please review the jpackage fix for bug [1] at [2]. This is a fix for the JDK-8200758-branch branch of the open sandbox repository (jpackage). This fix: Adds "app-image" as a valid value for "--package-type" options, meaning build an application image instead of a package. Changes the defau

RFR (s): 8176894 Provide specialized implementation for default methods putIfAbsent, computeIfAbsent, computeIfPresent, compute, merge in TreeMap

Hello everybody! Another one gentle reminder: please review the changeset and the CSR. Please note that the change is not that big: it's only several new methods in single TreeMap class, a few new unit-tests, and a benchmark. Here's issue: https://bugs.openjdk.java.net/browse/JDK-8176894 Webrev: h