added test cases for test files from alex, assertion is using the number of AST elements as a verification

fixed bugs in the transformations of the files in crewrite/src/test/resources/ifdeftoif_testfiles 1-7

Fixes:
Added more case classes which will be analyzed by getNextVariableFeaturesCondition and getNextFeaturesForVariableIdentifiers
Fixed a case where the currentContext gets lost in StructDeclarations
and maybe some more