RFR: JDK-8353755 : Add a helper method to Util - findComponent() [v3]

[Harshitha Onkar]

> `findComponent(final Container container, final Predicate<Component> predicate)` is a useful utility method and thus added to` javax/swing/regtesthelpers/Util.java` instead of having redundant code in tests. It can be used to find a component by label name.
> 
> PS: Existing `Util.findSubComponent()` finds component by class name but `findComponent()` can be used to search for a particular component by label name/title when there are multiple subcomponents of same type by applying a predicate logic.

Harshitha Onkar has updated the pull request incrementally with one additional commit since the last revision:

  Review changes: EDT check

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Changes:
  - all: https://git.openjdk.org/jdk/pull/27944/files
  - new: https://git.openjdk.org/jdk/pull/27944/files/6bc90058..cec6a0ca

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=27944&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=27944&range=01-02

  Stats: 24 lines in 3 files changed: 18 ins; 1 del; 5 mod
  Patch: https://git.openjdk.org/jdk/pull/27944.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27944/head:pull/27944

PR: https://git.openjdk.org/jdk/pull/27944