RFR: 8272137: Make Iterable classes streamable

[CC007]

create Streamable and ParallelStreamable interface and use them in Collection and Optional

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Commit messages:
 - 8272137: no CR
 - 8272137: create Streamable and ParallelStreamable interface and use in Collection and Optional

Changes: https://git.openjdk.java.net/jdk/pull/5050/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=5050&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8272137
  Stats: 104 lines in 4 files changed: 101 ins; 0 del; 3 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5050.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5050/head:pull/5050

PR: https://git.openjdk.java.net/jdk/pull/5050