RFR: Merge jdk:master

[Kevin Rushforth]

Manual merge of `jdk/master` into `lanai/master` since the nightly auto-merge process is _still_ offline (see [SKARA-764](https://bugs.openjdk.java.net/browse/SKARA-764)).

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Commit messages:
 - Merge jdk:master
 - 8255720: Optimize bci_to_dp/-data by enabling iteration over raw DataLayouts
 - 8255721: Remove no-op clean_weak_method_links methods
 - 8255544: Create a checked cast
 - 8255734: VM should ignore SIGXFSZ on ppc64, s390 too
 - 6816284: Notepad class should be public
 - 7124397: [macosx] JSpinner serialiazation - deserialization issue
 - 8255697: LogTargetHandle::print should check if log level is enabled
 - 8233637: [TESTBUG] Swing ActionListenerCalledTwiceTest.java fails on macos
 - 8233641: [TESTBUG] JMenuItem test bug4171437.java fails on macos
 - ... and 119 more: https://git.openjdk.java.net/lanai/compare/d9d2c0ad...87343a13

The webrevs contain the adjustments done while merging with regards to each parent branch:
 - master: https://webrevs.openjdk.java.net/?repo=lanai&pr=123&range=00.0
 - jdk:master: https://webrevs.openjdk.java.net/?repo=lanai&pr=123&range=00.1

Changes: https://git.openjdk.java.net/lanai/pull/123/files
  Stats: 17199 lines in 566 files changed: 10175 ins; 4779 del; 2245 mod
  Patch: https://git.openjdk.java.net/lanai/pull/123.diff
  Fetch: git fetch https://git.openjdk.java.net/lanai pull/123/head:pull/123

PR: https://git.openjdk.java.net/lanai/pull/123