RFR: 8268056: Update java.net and java.nio to use switch expressions [v6]

[Patrick Concannon]

> Hi,
> 
> Could someone please review my code for updating the code in the `java.net` and `java.nio` packages to make use of the switch expressions?
> 
> Kind regards,
> Patrick

Patrick Concannon has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains eight additional commits since the last revision:

 - 8268056: renamed variable in Files
 - Merge remote-tracking branch 'origin/master' into JDK-8268056
 - Merge remote-tracking branch 'origin/master' into JDK-8268056
 - 8268056: Added yield to switch expression in Files
 - 8268056: reverted changes to FileTime
 - Merge remote-tracking branch 'origin/master' into JDK-8268056
 - 8268056: Reverted changes to URLDecoder; reformatted change to FileTime
 - 8268056: Update java.net and java.nio to use switch expressions

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/4285/files
  - new: https://git.openjdk.java.net/jdk/pull/4285/files/0f7614e2..dec6d20b

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=4285&range=05
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=4285&range=04-05

  Stats: 6229 lines in 175 files changed: 4475 ins; 1291 del; 463 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4285.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4285/head:pull/4285

PR: https://git.openjdk.java.net/jdk/pull/4285