RFR: 8272778: Consolidate is_instance and is_instance_inlined in java_lang_String [v2]

[Albert Mingkun Yang]

> Simple change of merging `is_instance` and `is_instance_inlined`.
> 
> Test: build

Albert Mingkun Yang 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 three additional commits since the last revision:

 - more rename
 - Merge branch 'master' into inline
 - inline

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/5201/files
  - new: https://git.openjdk.java.net/jdk/pull/5201/files/883cc213..84b218a1

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=5201&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=5201&range=00-01

  Stats: 721 lines in 34 files changed: 581 ins; 73 del; 67 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5201.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5201/head:pull/5201

PR: https://git.openjdk.java.net/jdk/pull/5201