RFR: 8264126: Remove TRAPS/THREAD parameter for class loading functions [v2]

[Coleen Phillimore]

> find_constrained_instance_or_array_klass only passes THREAD so that it can be used in a MutexLocker for SystemDictionary_lock. This can use the MutexLocker that gets Thread::current() without any harm to performance.
> 
> The other functions add_loader_constraint, record_linking_constraints, and check_signature_loaders fall out from that.
> 
> check_signature_loaders should throw an exception but it unfortunately makes the caller construct the exception message so it doesn't.
> 
> Also: is_shared_class_visible{_impl}
> 
> Tested with tier1 on 4 Oracle platforms (in progress)

Coleen Phillimore has updated the pull request incrementally with one additional commit since the last revision:

  Improvements suggested by Ioi.

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/3176/files
  - new: https://git.openjdk.java.net/jdk/pull/3176/files/82b984e3..1e9e29cf

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=3176&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=3176&range=00-01

  Stats: 19 lines in 3 files changed: 3 ins; 1 del; 15 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3176.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3176/head:pull/3176

PR: https://git.openjdk.java.net/jdk/pull/3176