RFR: 8255562: delete UseRDPCForConstantTableBase [v3]

[Xin Liu]

> UseRDPCForConstantTableBase was a SPARC-exclusive flag. Sparc has been removed 
> from hotspot, so remove this flag.

Xin Liu 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 two additional commits since the last revision:

 - 8255562: delete UseRDPCForConstantTableBase
   
   mark UseRDPCForConstantTableBase is obsoletd in jdk16 and will expire in jdk17.
 - 8255562: delete UseRDPCForConstantTableBase

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/949/files
  - new: https://git.openjdk.java.net/jdk/pull/949/files/478aab95..ae686179

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=949&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=949&range=01-02

  Stats: 12770 lines in 658 files changed: 7121 ins; 3260 del; 2389 mod
  Patch: https://git.openjdk.java.net/jdk/pull/949.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/949/head:pull/949

PR: https://git.openjdk.java.net/jdk/pull/949