RFR: jsr166 integration 2018-09

[Martin Buchholz]

https://cr.openjdk.java.net/~martin/webrevs/jdk/jsr166-integration/overview.html

8210971: Add exception handling methods to CompletionStage and CompletableFuture
https://cr.openjdk.java.net/~martin/webrevs/jdk/jsr166-integration/exceptionally/index.html
https://bugs.openjdk.java.net/browse/JDK-8210971

8207003: Miscellaneous changes imported from jsr166 CVS 2018-09
https://cr.openjdk.java.net/~martin/webrevs/jdk/jsr166-integration/miscellaneous/index.html
https://bugs.openjdk.java.net/browse/JDK-8207003

This one continues to be stuck in CSR limbo:

8203662: remove increment of modCount from ArrayList and Vector replaceAll()
https://cr.openjdk.java.net/~martin/webrevs/jdk/jsr166-integration/replaceAll/index.html
https://bugs.openjdk.java.net/browse/JDK-8203662