RFR: 8349814: [leyden] Reduce uncommon traps in preload code [v8]

[Aleksey Shipilev]

> Preload code is the C2 code we load very early, before it gets substituted by more advanced C2 code. We are seeing lots of uncommon traps from the preloaded code, though, which invalidates it too early. We can do precompile code without uncommon traps to alleviate this. 
> 
> Additional testing:
>  - [x] Ad-hoc perf tests (see comment below)
>  - [x] Linux x86_64 server fastdebug, `runtime/cds`

Aleksey Shipilev has updated the pull request incrementally with one additional commit since the last revision:

  Also a script

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Changes:
  - all: https://git.openjdk.org/leyden/pull/38/files
  - new: https://git.openjdk.org/leyden/pull/38/files/116fa717..e600741e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=leyden&pr=38&range=07
 - incr: https://webrevs.openjdk.org/?repo=leyden&pr=38&range=06-07

  Stats: 33 lines in 1 file changed: 33 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/leyden/pull/38.diff
  Fetch: git fetch https://git.openjdk.org/leyden.git pull/38/head:pull/38

PR: https://git.openjdk.org/leyden/pull/38