Sema: TypeChecker::computeCaptures() and friends should be static

lib/Sema/DebuggerTestingTransform.cpp

@@ -242,7 +242,7 @@ private:
 
     // Captures have to be computed after the closure is type-checked. This
     // ensures that the type checker can infer <noescape> for captured values.
-    TC.computeCaptures(Closure);
+    TypeChecker::computeCaptures(Closure);
 
     return {false, FinalExpr};
   }