Dont' use system line seperator in CfFrontendExamplesTest

Seems that on windows asm still uses the linux one.

Change-Id: I34f3283d9dd5dfd98b1d4b73fb2e9411a8c3c5cc
diff --git a/src/test/java/com/android/tools/r8/CfFrontendExamplesTest.java b/src/test/java/com/android/tools/r8/CfFrontendExamplesTest.java
index 3f0d0be..a6578ee 100644
--- a/src/test/java/com/android/tools/r8/CfFrontendExamplesTest.java
+++ b/src/test/java/com/android/tools/r8/CfFrontendExamplesTest.java
@@ -346,7 +346,7 @@
       } else {
         expected.append(line);
       }
-      expected.append(StringUtils.LINE_SEPARATOR);
+      expected.append('\n');
     }
     return expected.toString();
   }