RFR: 8355432: Remove CompileTask from SA

[Aleksey Shipilev]

A lot of SA infrastructure was added to support SA compiler replay with [JDK-7088955](https://bugs.openjdk.org/browse/JDK-7088955). With [JDK-8315488](https://bugs.openjdk.org/browse/JDK-8315488), we got rid from the most of it. `CompileTask` seems to be left behind. Nothing uses it in SA now.

Now, for Leyden, we want to massage `CompileTask` for better performance and reliability ([JDK-8231269](https://bugs.openjdk.org/browse/JDK-8231269)), and keeping `CompileTask` in SA would require us to implement a whole bunch of complicated, but unnecessary code.

So, it would be good to purge `CompileTask` from SA.

Note that I left the related `vmStructs` definitions, because async-profiler uses those; I think to see which methods current compiler is compiling. That use looks safe, as it polls the task from the already set up ciEnv. Anyway, it is async-profiler's headache to deal with `vmStruct` changes.

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Commit messages:
 - Fix

Changes: https://git.openjdk.org/jdk/pull/24832/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=24832&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8355432
  Stats: 73 lines in 1 file changed: 0 ins; 73 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/24832.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24832/head:pull/24832

PR: https://git.openjdk.org/jdk/pull/24832