RFR: 8300487: Store cardinality as a field in BitSet [v3]

[fabioromano1]

> The enanchment is useful for applications that make heavy use of BitSet objects as sets of integers, and therefore they need to make a lot of calls to cardinality() method, which actually require linear time in the number of words in use by the bit set.
> This optimization reduces the cost of calling cardinality() to constant time, as it simply returns the value of the field, and it also try to make as little effort as possible to update the field, when needed.
> 
> Moreover, it has been implemented a new method for testing wheter a bit set includes another bit set (i.e., the set of true bits of the parameter is a subset of the true bits of the instance).

fabioromano1 has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 43 additional commits since the last revision:

 - Merge branch 'openjdk:master' into patch-2
 - Added author to includes(BitSet)
 - Removed trailing spaces
 - Format file
 - Format file
 - Formatted
 - Added this. in BitSet(long[])
 - Merge branch 'openjdk:master' into patch-2
 - Merge branch 'openjdk:master' into patch-2
 - Merge branch 'openjdk:master' into patch-2
 - ... and 33 more: https://git.openjdk.org/jdk/compare/d391b89f...206e967d

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/11837/files
  - new: https://git.openjdk.org/jdk/pull/11837/files/d06ed69d..206e967d

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=11837&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=11837&range=01-02

  Stats: 9034 lines in 717 files changed: 5331 ins; 1260 del; 2443 mod
  Patch: https://git.openjdk.org/jdk/pull/11837.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11837/head:pull/11837

PR: https://git.openjdk.org/jdk/pull/11837