Changes

This is a first idea how to cache pragmas
-> Pragma class has a Dictionary with one entry per selector 
-> It references the Pragmas weakly

CompiledMethods add their pragmas to the cache when they are added in a class.

Speed to get all pragmas:

[Pragma allInstalled] bench "'799.320 per second'".
[PragmaCollector allSystemPragmas] bench  "'54.923 per second'"

But it will now grow with the number of pragmas, not number of methods.

Pragma allNamed: aSymbol can replace the use of the PragmaCollector in many cases (to be explored)

This PR just adds the Cache and tests, it is not yet used. The next step is to test it a bit, compare it with #allSystemPragmas and
the implement allSystemPragmas to use the cache.

fix a test: add to AbstractObjectsAsMethod api cachePragmas

- fix typo
- recategorize API method
- improve tests

ClassDescription stores RemoteString instances. But that is not needed: we can store instead the sourcepointer (as we do with CompiledMethod).

Why is this better? it removes one instance of RemoteString per class comment from the image, saving memory espeically for images with many well documented classes.

CatalogBrowser can use the API that we have to get pragmas from one class. This ommits iterating the whole system to find pragmas

fixes #6839

Fix #7222
All #acceptVisitor: should return the result of the visit

The compiler is doing far too much magic in #isInteractiveFor:

It allows #isInteractive to not be implemented on the requestor. But even if it is, it does a nil check.

As a first improvement, we require that #interactive has to return a boolean if it exists.

make sure that two of the users return false if the var is nil

- change CopyingLocalVariable to CopiedLocalVariable ("this variable is copied"), in line with #createCopiedVariableFor:
- simplify OCUndeclaredVariableWarning>>#defaultAction a little

Fix #7219
Produce a valid AST (for methods)

Fix #7217
RBEOFToken should have an empty value. Otherwise it has a wrong stop and source interval.

Fix #7214
If in scripting mode, rubric should parse expressions and not methods.
Clean commented code.

Add support for completing shared pools

This PR adds support to decompile Clean Blocks.