Replace `ifNil:[...]` with `isNil ifTrue:[...]`
The latter is optimized by compilers and therefore faster.
"{ Package: 'stx:goodies/petitparser/compiler/tests' }"
"{ NameSpace: Smalltalk }"
PPContextMementoTest subclass:#PPCContextMementoTest
instanceVariableNames:''
classVariableNames:''
poolDictionaries:''
category:'PetitCompiler-Tests-Context'
!
!PPCContextMementoTest methodsFor:'as yet unclassified'!
memento
^ PPCContextMemento new
! !
!PPCContextMementoTest class methodsFor:'documentation'!
version_HG
^ '$Changeset: <not expanded> $'
! !