RFR: 8223078: Add microbenchmark for array copying/clearing/resizing

[Martin Buchholz]

8223078: Add microbenchmark for array copying/clearing/resizing
https://cr.openjdk.java.net/~martin/webrevs/jdk/ArrayFiddle-jmh/
https://bugs.openjdk.java.net/browse/JDK-8223078