RFR: JDK-8286615: Small refactor to SerializedLambda

[Joe Darcy]

Noticed by inspection during a CSR review, small refactoring to use a message-cause exception constructor when one is available.

Will update the copyright before a push.

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Commit messages:
 - JDK-8286615: Small refactor to SerializedLambda

Changes: https://git.openjdk.java.net/jdk/pull/8670/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8670&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8286615
  Stats: 3 lines in 1 file changed: 0 ins; 2 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8670.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8670/head:pull/8670

PR: https://git.openjdk.java.net/jdk/pull/8670