RFR: 8140442: Add getOutermostTypeElement to javax.lang.model utility class [v2]

[Joe Darcy]

> Please review this change to add a getOutermostTypeElement method to javax.lang.model.Elements along with the corresponding CSR https://bugs.openjdk.java.net/browse/JDK-8271903.

Joe Darcy has updated the pull request incrementally with one additional commit since the last revision:

  Respond to review feedback and update copyright.

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/5007/files
  - new: https://git.openjdk.java.net/jdk/pull/5007/files/bc1de3f0..3ac05554

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=5007&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=5007&range=00-01

  Stats: 5 lines in 3 files changed: 0 ins; 1 del; 4 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5007.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5007/head:pull/5007

PR: https://git.openjdk.java.net/jdk/pull/5007