New plan to [fix the `sbt` build](https://www.pivotaltracker.com/n/projects/2539304/stories/182209126) and its annoying:
```
log.error(
"Truffle Instrumentation is not up to date, " +
"which will lead to runtime errors\n" +
"Fixes have been applied to ensure consistent Instrumentation state, " +
"but compilation has to be triggered again.\n" +
"Please re-run the previous command.\n" +
"(If this for some reason fails, " +
s"please do a clean build of the $projectName project)"
)
```
When it is hard to fix `sbt` incremental compilation, let's restructure our project sources so that each `@TruffleInstrument` and `@TruffleLanguage` registration is in individual compilation unit. Each such unit is either going to be compiled or not going to be compiled as a batch - that will eliminate the `sbt` incremental compilation issues without addressing them in `sbt` itself.
fa2cf6a33ec4a5b2e3370e1b22c2b5f712286a75 is the first step - it introduces `IdExecutionService` and moves all the `IdExecutionInstrument` API up to that interface. The rest of the `runtime` project then depends only on `IdExecutionService`. Such refactoring allows us to move the `IdExecutionInstrument` out of `runtime` project into independent compilation unit.
Incremental compilation of instruments may lead to runtime errors when
only some of the instruments are recompiled (because the unchanged
instruments are not registered by the Annotation Processor).
To fix this, we add a task that ensures all instruments are recompiled
when at least one of them changes.
