RFR: 8377307: Refactor code for AOT cache pointer compression [v2]

[Ioi Lam]

> AOT cache uses pointer compression to store 64-bit pointers in 32 bits. Currently the compression algorithm is simply (base + narrowPtr). However, in [JDK-8376125](https://bugs.openjdk.org/browse/JDK-8376125), we may change it to (base + narrowPtr << 3).
> 
> This RFE changed the encoded pointer from an u4 to (thanks to @jdksjolen for the idea):
> 
> 
> enum class narrowPtr : u4;
> 
> 
> This allows better tracking of where the encoded pointers are stored. Also, we can distinguish between byte offsets vs encoded pointers -- they currently have the same numerical values but after [JDK-8376125](https://bugs.openjdk.org/browse/JDK-8376125), they will be different.
> 
> Also minor clean up in ArchiveBuilder to change some `uintx` to `size_t`, which is used by `pointer_delta()`.

Ioi Lam has updated the pull request incrementally with two additional commits since the last revision:

 - restored assert
 - @jdksjolen review comments

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/29590/files
  - new: https://git.openjdk.org/jdk/pull/29590/files/3b2e2057..7c4a3a50

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=29590&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=29590&range=00-01

  Stats: 86 lines in 9 files changed: 5 ins; 34 del; 47 mod
  Patch: https://git.openjdk.org/jdk/pull/29590.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/29590/head:pull/29590

PR: https://git.openjdk.org/jdk/pull/29590