RFR: 8292170: Convert CodeRootSetTable to use ResourceHashtable [v10]

[Leo Korinth]

> I am replacing the old hash table with ResourceHashtable. In the process I am also removing the redundant `_length` field. By removing the `_length` field, a lot of asserts can be removed as the length will trivially match the length of the underlying table.
> 
> I would like to have feedback on the addition of `unlink_destruct(Function&& should_remove)`. I added it because I prefer to use a functor object that can be used by lambdas instead of an iterator object. However, I did add code to "destruct" resource objects when they are removed instead of just letting them be to reflect that we use `delete` on c-heap objects. Maybe I should remove this "improvement" and then maybe implement the function by calling the existing unlink?

Leo Korinth has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 13 commits:

 - Merge branch '_master_jdk' into _8292170
 - include cleanups, test fix
 - Remove the purge list and use the resizing of the resource hash
   table.
   
   Add asserts ensuring that we do not mutatet a hash table while we
   iterate over it. Renaming .*g1CodeCacheRemSet.?pp -> .*g1CodeRootSet.?pp
 - code_roots_list_contains is now locked, but we have problems with add() during nmethods_do
 - revert copyright year after changes
 - add mem_size() method to resourceHash.hpp
 - can not use contains in combination with add without a lock
 - remove specialized hash
 - inline g1CodeRootSetTable.hpp
 - remove unused template
 - ... and 3 more: https://git.openjdk.org/jdk/compare/b678e700...6e1832a2

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Changes: https://git.openjdk.org/jdk/pull/11675/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=11675&range=09
  Stats: 899 lines in 18 files changed: 301 ins; 585 del; 13 mod
  Patch: https://git.openjdk.org/jdk/pull/11675.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11675/head:pull/11675

PR: https://git.openjdk.org/jdk/pull/11675