RFR: 8368465: [leyden] Improve precompiler method selection code [v2]

[Aleksey Shipilev]

> Forked from [JDK-8366681](https://bugs.openjdk.org/browse/JDK-8366681): there are still some cleanups/performance improvements possible. Current selection code is a bit hairy, and turns out the changes I made for previous patch improve performance.
> 
> Notable improvements:
>  1. Push the compilation level filters downwards. This allows compiling A2 from T2/T3 code more easily, and allows to implement policies for compiling on any A* level based on observing top-compiled T* levels.
>  2. Sort methods by hotness and code size. This avoids a fairly awkward path to get compile IDs, ditching which _I suspect_ is the cause for performance improvement. With new code, we compile a tad more A2 code. I have not digged through why current code accepts fewer methods for compilation. New code improves performance everywhere, so I suggest we just accept that and move on.
> 
> Additional testing:
>  - [x] Performance tests (see comments)
>  - [x] Linux x86_64 server fastdebug, `runtime/cds`

Aleksey Shipilev has updated the pull request incrementally with two additional commits since the last revision:

 - Touchup
 - Touchups

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

Changes:
  - all: https://git.openjdk.org/leyden/pull/99/files
  - new: https://git.openjdk.org/leyden/pull/99/files/d63bde8e..77b8b3ef

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=leyden&pr=99&range=01
 - incr: https://webrevs.openjdk.org/?repo=leyden&pr=99&range=00-01

  Stats: 6 lines in 1 file changed: 3 ins; 2 del; 1 mod
  Patch: https://git.openjdk.org/leyden/pull/99.diff
  Fetch: git fetch https://git.openjdk.org/leyden.git pull/99/head:pull/99

PR: https://git.openjdk.org/leyden/pull/99