RFR: 8274945: Cleanup unnecessary calls to Throwable.initCause() in java.desktop

[Andrey Turbanov]

Pass cause exception as constructor parameter is shorter and easier to read.

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Commit messages:
 - [PATCH] Cleanup unnecessary calls to Throwable.initCause() in java.desktop module

Changes: https://git.openjdk.java.net/jdk/pull/5847/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=5847&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8274945
  Stats: 21 lines in 4 files changed: 0 ins; 15 del; 6 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5847.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5847/head:pull/5847

PR: https://git.openjdk.java.net/jdk/pull/5847