RFR: 8267611: Print more info when pointer_delta assert fails

[Stefan Karlsson]

We've seen a few new failures with the new pointer_delta assert. It would be nice if the assert printed the 'left' and 'right' pointer values.

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

Commit messages:
 - 8267611: Print more info when pointer_delta assert fails

Changes: https://git.openjdk.java.net/jdk/pull/4163/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=4163&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8267611
  Stats: 15 lines in 1 file changed: 9 ins; 5 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4163.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4163/head:pull/4163

PR: https://git.openjdk.java.net/jdk/pull/4163