RFR: 8297503: Merge FilteringDCTOC into ContiguousSpaceDCTOC [v2]

[Albert Mingkun Yang]

> Simple cleanup of trimming unnecessary type hierarchy levels.
> 
> Test: hotspot_gc

Albert Mingkun Yang has updated the pull request incrementally with one additional commit since the last revision:

  review

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/11322/files
  - new: https://git.openjdk.org/jdk/pull/11322/files/0b7fa701..0c20768c

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=11322&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=11322&range=00-01

  Stats: 2 lines in 1 file changed: 1 ins; 1 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/11322.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11322/head:pull/11322

PR: https://git.openjdk.org/jdk/pull/11322