add newline to end of file

Author: spall

clang/test/SemaHLSL/Language/FlatCast-errors.hlsl

@@ -5,4 +5,4 @@ export void cantCast() {
   int B[4] = {1,2,3,4};
   B = (int[4])A;
   // expected-error@-1 {{C-style cast from 'int *' to 'int[4]' is not allowed}}
-}
+}