RFR: 8331108: Unused Math.abs call in java.lang.FdLibm.Expm1#compute

[Joe Darcy]

Remove unnecessary setting of variable y, found by an IDE inspection noted in the bug report.

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Commit messages:
 - JDK-8331108: Unused Math.abs call in java.lang.FdLibm.Expm1#compute

Changes: https://git.openjdk.org/jdk/pull/18963/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=18963&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8331108
  Stats: 1 line in 1 file changed: 0 ins; 1 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/18963.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18963/head:pull/18963

PR: https://git.openjdk.org/jdk/pull/18963