[Trait] Impossible to use from a classTrait a method that is also defined in a subclass of Behavior even when following the doc

[VincentBlondeau]

Following of #3389

So I try what is written in the doc, and it happens that it fails. I expect that the Trait MyTrait takes the lead on the methods that are defined on the class side.

Example to reproduce the issue:

Trait
	named: #MyTrait
	uses: {}
	category: 'TestTrait'.

(Smalltalk globals at: #MyTrait) classTrait compile: 'obsolete2 ^true' classified: 'testing'.
(Smalltalk globals at: #Behavior)  compile: 'obsolete2 ^false' classified: 'testing'.
(Smalltalk globals at: #TraitedClass)  compile: 'obsolete2 ^false' classified: 'testing'.


Object subclass: #MyTraitUser
	uses: (Smalltalk globals at: #MyTrait) 
	instanceVariableNames: ''
	classVariableNames: ''
	package: 'TestTrait'.

self assert: (Smalltalk globals at: #MyTraitUser) class obsolete2

[VincentBlondeau]

With the previous commit, this assertion is true:

self assert: ((Smalltalk globals at: #MyTraitUser) class >> #obsolete) sourceCode
 = 'obsolete ^true'.

But sill not this one...
self assert: (Smalltalk globals at: #MyTraitUser) class obsolete2

[VincentBlondeau]

Actually the good assertion is self assert: (Smalltalk globals at: #MyTraitUser) obsolete2 and not self assert: (Smalltalk globals at: #MyTraitUser) class obsolete2

[VincentBlondeau]

Tests still should be added related to #3426 .

Backport have to be done too

[VincentBlondeau]

There is still an issue when there is a trait that is already used in the superclass. The subclass does not contain the right method. Test will be added in a PR

[VincentBlondeau]

#3906 should be integrated too