RFR: 8285696: AlgorithmConstraints:permits not throwing IllegalArgumentException when 'alg' is null [v2]

[Daniel Jeliński]

> Please review this follow up to #8349.
> 
> As JCK pointed out, `permits` is supposed to throw IAE on null input. However, now that we're looking up the result in a `ConcurrentHashMap`, a `NullPointerException` is thrown. This patch restores the original behavior.
> 
> Verified that the JCK test passes with this change.

Daniel Jeliński has updated the pull request incrementally with one additional commit since the last revision:

  Move check to permits method

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/8427/files
  - new: https://git.openjdk.java.net/jdk/pull/8427/files/35361a31..6eb0d50e

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=8427&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=8427&range=00-01

  Stats: 6 lines in 1 file changed: 3 ins; 3 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8427.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8427/head:pull/8427

PR: https://git.openjdk.java.net/jdk/pull/8427