RFR: 8310494: Do not include constantPool.hpp from instanceKlass.hpp [v2]

[Ioi Lam]

> instanceKlass.hpp is needed quite frequently for HotSpot C++ sources, but constantPool.hpp is much less frequently.
> 
> This PR is the first step of reducing the inclusion of constantPool.hpp, by removing it from instanceKlass.hpp
> 
> I moved a bunch of inline functions into instanceKlass.cpp. These don't seem to be performance related.

Ioi Lam has updated the pull request incrementally with one additional commit since the last revision:

  @stefank review comments

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Changes:
  - all: https://git.openjdk.org/jdk/pull/14597/files
  - new: https://git.openjdk.org/jdk/pull/14597/files/8c12d578..68697195

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=14597&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=14597&range=00-01

  Stats: 3 lines in 2 files changed: 1 ins; 1 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/14597.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14597/head:pull/14597

PR: https://git.openjdk.org/jdk/pull/14597