Remove target-following code when erasing signatures
Remove target-following code when erasing signatures

Fixes return type of inherited default constructors when they are
generic.

DLehenbauer/TypeScript,mihailik/TypeScript,TukekeSoft/TypeScript,kitsonk/TypeScript,Microsoft/TypeScript,erikmcc/TypeScript,basarat/TypeScript,minestarks/TypeScript,basarat/TypeScript,donaldpipowitch/TypeScript,SaschaNaz/TypeScript,mihailik/TypeScript,alexeagle/TypeScript,TukekeSoft/TypeScript,donaldpipowitch/TypeScript,plantain-00/TypeScript,TukekeSoft/TypeScript,Microsoft/TypeScript,nojvek/TypeScript,vilic/TypeScript,alexeagle/TypeScript,RyanCavanaugh/TypeScript,erikmcc/TypeScript,vilic/TypeScript,plantain-00/TypeScript,microsoft/TypeScript,alexeagle/TypeScript,synaptek/TypeScript,DLehenbauer/TypeScript,SaschaNaz/TypeScript,donaldpipowitch/TypeScript,erikmcc/TypeScript,chuckjaz/TypeScript,SaschaNaz/TypeScript,DLehenbauer/TypeScript,Eyas/TypeScript,mihailik/TypeScript,Eyas/TypeScript,kitsonk/TypeScript,jwbay/TypeScript,kpreisser/TypeScript,chuckjaz/TypeScript,Eyas/TypeScript,basarat/TypeScript,Microsoft/TypeScript,weswigham/TypeScript,minestarks/TypeScript,jeremyepling/TypeScript,synaptek/TypeScript,microsoft/TypeScript,nojvek/TypeScript,synaptek/TypeScript,erikmcc/TypeScript,RyanCavanaugh/TypeScript,synaptek/TypeScript,mihailik/TypeScript,thr0w/Thr0wScript,kpreisser/TypeScript,jeremyepling/TypeScript,weswigham/TypeScript,donaldpipowitch/TypeScript,weswigham/TypeScript,nojvek/TypeScript,vilic/TypeScript,thr0w/Thr0wScript,kitsonk/TypeScript,jeremyepling/TypeScript,chuckjaz/TypeScript,nojvek/TypeScript,RyanCavanaugh/TypeScript,plantain-00/TypeScript,vilic/TypeScript,SaschaNaz/TypeScript,thr0w/Thr0wScript,Eyas/TypeScript,jwbay/TypeScript,minestarks/TypeScript,plantain-00/TypeScript,jwbay/TypeScript,thr0w/Thr0wScript,jwbay/TypeScript,chuckjaz/TypeScript,basarat/TypeScript,kpreisser/TypeScript,DLehenbauer/TypeScript,microsoft/TypeScript