RFR: 8253086: Optimization of removeAll and retainAll of ObservableListWrapper

[yosbits]

https://bugs.openjdk.java.net/browse/JDK-8253086

ObservableListWrapper.java
 * public boolean removeAll(Collection<?> c)
* public boolean retainAll(Collection<?> c)

These two methods use BitSet, but it doesn't make sense.
By rewriting to the equivalent behavior that does not use BitSet, it is possible to reduce the CPU load in a wide range
of use cases.

The test is done with the following command.

* gradle base: test
* gradle controls: test

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Commit messages:
 - 8253086: Optimization of removeAll and retainAll of ObservableListWrapper

Changes: https://git.openjdk.java.net/jfx/pull/305/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jfx&pr=305&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8253086
  Stats: 26 lines in 1 file changed: 6 ins; 10 del; 10 mod
  Patch: https://git.openjdk.java.net/jfx/pull/305.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx pull/305/head:pull/305

PR: https://git.openjdk.java.net/jfx/pull/305