RFR: 8253880: clean up sun/hotspot/tools/ctw/Utils class

[Igor Ignatyev]

Hi all,

could you please review this trivial clean up in sun/hotspot/tools/ctw/Utils which removes unused `PATH_SEPARATOR`
field and unused imports?

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Commit messages:
 - 8253880: clean up sun/hotspot/tools/ctw/Utils class

Changes: https://git.openjdk.java.net/jdk/pull/444/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=444&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8253880
  Stats: 8 lines in 1 file changed: 0 ins; 8 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/444.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/444/head:pull/444

PR: https://git.openjdk.java.net/jdk/pull/444