anchor.diff:    FastaContext(
         this.vm,
         this.strongMode,
  +      this.platformBinaries,
         this.onlyCrashes,
         bool ignoreExpectations,
         bool updateExpectations,
  
positive.code:   final bool strongMode;
    final bool onlyCrashes;
    final Map<Program, KernelTarget> programToTarget = <Program, KernelTarget>{};
    Uri platformBinaries;
    Uri platformUri;
    Uri outlineUri;
    Program outline;
  
negative.code:   }
  
    Future ensurePlatformUris() async {
      if (platformUri == null) {
        platformUri = platformBinaries.resolve("vm_platform.dill");
        outlineUri = platformBinaries
            .resolve(strongMode ? "vm_outline_strong.dill" : "vm_outline.dill");
  