Fix InliningWithoutPositions test on ART 4.4.4

4.4.4 stack traces end at dalvik.system.NativeStart.main instead of
application's main, that's why it failed.
Removing the assert checking that is fine since we always expect a
single stack frame at application's main, no need to check what's
further down.

Bug:
Change-Id: I12f3e63a781413056b397dc9641fa56cb89469cb
diff --git a/src/test/java/com/android/tools/r8/debuginfo/InliningWithoutPositionsTestRunner.java b/src/test/java/com/android/tools/r8/debuginfo/InliningWithoutPositionsTestRunner.java
index 4f19cfd..c67cf32 100644
--- a/src/test/java/com/android/tools/r8/debuginfo/InliningWithoutPositionsTestRunner.java
+++ b/src/test/java/com/android/tools/r8/debuginfo/InliningWithoutPositionsTestRunner.java
@@ -146,9 +146,6 @@
     int idxAfter = idx + expectedFilePos.length();
     assertTrue(idxAfter == line.length() || !Character.isDigit(line.charAt(idxAfter)));
 
-    // There should be no further stack trace line after this.
-    assertTrue(lines.length == i + 1 || !lines[i + 1].trim().startsWith("at"));
-
     // Reading the Proguard map. An example map (only the relevant part, 'main'):
     //
     //     1:1:void bar():0:0 -> main