RFR: 8261031: Move some ClassLoader name checking to native/VM [v2]

[Claes Redestad]

> This patch moves some sanity checking done in ClassLoader.java to the corresponding endpoints in native or VM code.

Claes Redestad 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 'master' into checkName
 - Merge branch 'master' into checkName
 - Copyrights
 - Move class name checking for findBootstrapClass/findLoadedClass into native/VM

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/2378/files
  - new: https://git.openjdk.java.net/jdk/pull/2378/files/f2fd1d1c..727b2b37

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=2378&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=2378&range=00-01

  Stats: 28701 lines in 954 files changed: 16489 ins; 8085 del; 4127 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2378.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2378/head:pull/2378

PR: https://git.openjdk.java.net/jdk/pull/2378