RFR: 8273514: java/util/DoubleStreamSums/CompensatedSums.java failure

[Ian Graves]

Relaxing some assertion bounds to allow for small error values that still show improvement over previous summation method.

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

Commit messages:
 - Dropping unnecessary equals case
 - Dropping equals zero assert

Changes: https://git.openjdk.java.net/jdk/pull/5430/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=5430&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8273514
  Stats: 3 lines in 1 file changed: 0 ins; 3 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5430.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5430/head:pull/5430

PR: https://git.openjdk.java.net/jdk/pull/5430