RFR: JDK-8270476: Make floating-point test infrastructure more lambda and method reference friendly

[Joe Darcy]

Update the java.lang.{Math, StrictMath} regression test helper library to accept method references. This allows the test programs to be DRY-er as the inputs to the method under test don't have to be repeated. The float test method were not updated due to limitations in type inference if both float and double methods with functional interface parameters are present.

Also did some general tidying up for the test code.

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

Commit messages:
 - Appease jcheck.
 - Further refactoring.
 - Update copyright year, remove author tags.
 - JDK-8270476: Make floating-point test infrastructure more lambda and method reference friendly

Changes: https://git.openjdk.java.net/jdk/pull/7216/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=7216&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8270476
  Stats: 455 lines in 27 files changed: 118 ins; 145 del; 192 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7216.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7216/head:pull/7216

PR: https://git.openjdk.java.net/jdk/pull/7216