RFR: JDK-8282776: Bad NullPointerException message when invoking an interface MethodHandle on a null receiver [v4]

[Mandy Chung]

> A simple patch to call `Objects.requireNonNull(recv)` for an explicit null receiver check rather than NPE thrown by `Object::getClass`.  The message of NPE generated by JEP 358 (Helpful NullPointerExceptions) is supposed to be helpful but not in this case.

Mandy Chung has updated the pull request incrementally with one additional commit since the last revision:

  per feedback

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/7766/files
  - new: https://git.openjdk.java.net/jdk/pull/7766/files/62f74c70..55c38cf8

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=7766&range=03
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=7766&range=02-03

  Stats: 4 lines in 1 file changed: 2 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7766.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7766/head:pull/7766

PR: https://git.openjdk.java.net/jdk/pull/7766