RFR: 8274016: Replace 'for' cycles with iterator with enhanced-for in java.desktop [v3]

[Andrey Turbanov]

> There are few places in code where manual `for` loop is used with Iterator to iterate over Collection.
> Instead of manual `for` cycles it's preferred to use enhanced-for cycle instead: it's less verbose, makes code easier to read and it's less error-prone.
> It doesn't have any performance impact: java compiler generates similar code when compiling enhanced-for cycle.
> This is continuation of [JDK-8258006](https://bugs.openjdk.java.net/browse/JDK-8258006)

Andrey Turbanov has updated the pull request incrementally with one additional commit since the last revision:

  8274016: Replace 'for' cycles with iterator with enhanced-for in java.desktop
  drop useless comment
  cleanup unused imports

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/5578/files
  - new: https://git.openjdk.java.net/jdk/pull/5578/files/fe07b885..3a77c210

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=5578&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=5578&range=01-02

  Stats: 10 lines in 6 files changed: 0 ins; 10 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5578.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5578/head:pull/5578

PR: https://git.openjdk.java.net/jdk/pull/5578