RFR: 8272347: ObjectMethods::bootstrap should specify NPE if any argument except lookup is null [v2]

[Vicente Romero]

> Please review this simple PR along with the associated CSR. The PR is basically adding a line the the specification of method `java.lang.runtime.ObjectMethods::bootstrap` stating under what conditions a NPE will be thrown.
> 
> TIA
> 
> link to the [CSR](https://bugs.openjdk.java.net/browse/JDK-8272852)

Vicente Romero has updated the pull request incrementally with one additional commit since the last revision:

  addressing review comments

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/5226/files
  - new: https://git.openjdk.java.net/jdk/pull/5226/files/b7489b41..89086ca1

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=5226&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=5226&range=00-01

  Stats: 30 lines in 2 files changed: 17 ins; 1 del; 12 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5226.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5226/head:pull/5226

PR: https://git.openjdk.java.net/jdk/pull/5226