RFR: 8066622 8066637: remove deprecated using java.io.File.toURL() in internal classes

[Sebastian Ritter]

In result of Javadoc to do not use java.io.File.toURL()
Change use  java.io.File.toURL().toURI() instead.

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Commit messages:
 - in result of Javadoc to java.io.File.toURL do use internal java.io.File.toURL().toURI instead

Changes: https://git.openjdk.java.net/jdk/pull/1108/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=1108&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8066622
  Stats: 3 lines in 2 files changed: 0 ins; 0 del; 3 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1108.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1108/head:pull/1108

PR: https://git.openjdk.java.net/jdk/pull/1108