RFR: JDK-8281003 - MethodHandles::lookup throws NPE if caller is null [v2]

[Tim Prinzing]

> JDK-8281003 - MethodHandles::lookup throws NPE if caller is null

Tim Prinzing has updated the pull request incrementally with one additional commit since the last revision:

  Changes from feedback.
  
  - Improved javadoc.
  - Single copyright date in new files.
  - Informative string in exception that is thrown.
  - Shortened the test name.

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/7447/files
  - new: https://git.openjdk.java.net/jdk/pull/7447/files/1bb6316f..02d00ecb

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=7447&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=7447&range=00-01

  Stats: 152 lines in 5 files changed: 77 ins; 70 del; 5 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7447.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7447/head:pull/7447

PR: https://git.openjdk.java.net/jdk/pull/7447