RFR: 8314078: HotSpotConstantPool.lookupField() asserts due to field changes in ConstantPool.cpp

[Ioi Lam]

This PR updates Java code in JVMCI to match the C code changes in [JDK-8301996](https://bugs.openjdk.java.net/browse/JDK-8301996) that modified the constant pool layout. Essentially, the indices after a getfield/putfield/getstatic/putstatic bytecode is no longer a CpCacheIndex, but an index for `ConstantPool::resolved_field_entry_at(int field_index)`.

The assertion (and subsequent crash) happen only in debug builds. Out of pure luck, in product build JVMCI produces the correct output even after [JDK-8301996](https://bugs.openjdk.java.net/browse/JDK-8301996), although the code was doing the wrong thing.

This PR has (so far) two commits:

- 6527e67b1832087d180d2b50b65aaeca2e244c28 The actual functional change to use the `rawIndex` that follows a field bytecode.
- c322b8e71d4d9e33bd065e64420101010f9127fc Fixed incorrectly named parameters and variables in the JVMCI code and JavaDoc. In most cases, `cpi` needs to be changed to `rawIndex` to reflect the correct type of the index.

To help reviewing, I am limiting the renaming to just those affected by the field changes (without the renames, it's hard to validate that I am actually doing the right thing).

There are still some cases of `cpi` that need to be changed to `rawIndex`. I will fix those in a separate RFE. E.g. in ConstantPool.java:


default JavaMethod lookupMethod(int cpi, int opcode) {
    return lookupMethod(cpi, opcode, null);
}

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

Commit messages:
 - (no actual code changes) Fixed variable names and javadoc so that changes in this PR are consistent
 - 8314078: HotSpotConstantPool.lookupField() asserts due to field changes in ConstantPool.cpp

Changes: https://git.openjdk.org/jdk/pull/15237/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15237&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8314078
  Stats: 123 lines in 5 files changed: 62 ins; 8 del; 53 mod
  Patch: https://git.openjdk.org/jdk/pull/15237.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15237/head:pull/15237

PR: https://git.openjdk.org/jdk/pull/15237