Guard SoilPagedIndexStore>>#pageAt:put: against overrides

[MarcusDenker]

Make sure to never just override an exisiting page in the store.

We change SoilPagedIndexStore>>#pageAt:put: to use #at:ifPresent:ifAbsentPut: to raise an error in this case

[MarcusDenker]

In my image this was green, but it was not the latest version of Soil I think

[MarcusDenker]

So, indeed with he newest Soil this guard fails:

SoilBasicSkipList>>#splitPage:forKey:

is adding a page with a key that is already in the store

[MarcusDenker]

No, we need to be able to override a free page with a recycled page. Correct check is:

pageAt: anInteger put: aPage 
	
	^ pagesMutex critical: [  
		pages at: anInteger ifPresent: [:page | (page class == SoilFreePage) ifFalse: [ self error ]  ].
		pages 
			at: anInteger 
			put: aPage ] 

and that is green

[MarcusDenker]

(I close the Pr)