RFR: jsr166 integration 2018-07

[Martin Buchholz]

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

Some smallish changes; all of them already seen review elsewhere.

8206123: ArrayDeque created with default constructor can only hold 15
elements
http://cr.openjdk.java.net/~martin/webrevs/jdk/jsr166-integration/ArrayDeque-capacity/index.html
https://bugs.openjdk.java.net/browse/JDK-8206123

8205576: forkjoin/FJExceptionTableLeak.java fails "AssertionError: failed
to satisfy condition"
http://cr.openjdk.java.net/~martin/webrevs/jdk/jsr166-integration/FJExceptionTableLeak/index.html
https://bugs.openjdk.java.net/browse/JDK-8205576

8205620: Miscellaneous changes imported from jsr166 CVS 2018-07
http://cr.openjdk.java.net/~martin/webrevs/jdk/jsr166-integration/miscellaneous/index.html
https://bugs.openjdk.java.net/browse/JDK-8205620