RFR: 8328864: NullPointerException in sun.security.jca.ProviderList.getService() [v2]

[Ben Perez]

> Updated `getService` to check whether `getProvider` returns null when checking for preferred providers and `continue` the loop if that is the case. Added `NullPreferredList` test.

Ben Perez has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains four additional commits since the last revision:

 - Merge branch 'openjdk:master' into JDK-8328864
 - Fixed copyright, removed unnecessary null check in ProviderList
 - Fixed and renamed test, getService now continues loop instead of returning null
 - added test file

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Changes:
  - all: https://git.openjdk.org/jdk/pull/18746/files
  - new: https://git.openjdk.org/jdk/pull/18746/files/8ae0a7c3..7c5d682b

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=18746&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=18746&range=00-01

  Stats: 57336 lines in 1152 files changed: 25090 ins; 24163 del; 8083 mod
  Patch: https://git.openjdk.org/jdk/pull/18746.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18746/head:pull/18746

PR: https://git.openjdk.org/jdk/pull/18746