tests/dtx: test tagging of FACCH/[FH] frames

This patch adds a new test confirming that [1] actually fixes the bug.

Change-Id: I3d295a15d4446b3e440fbf4c90a1688d6c7275ae
Related: [1] I2e6f4b748c6445725211e264ab5f3f5a2712087a
Related: SYS#5853
diff --git a/tests/dtx/dtx_gsm0503_test.ok b/tests/dtx/dtx_gsm0503_test.ok
index 5f49cb0..750b440 100644
--- a/tests/dtx/dtx_gsm0503_test.ok
+++ b/tests/dtx/dtx_gsm0503_test.ok
@@ -21,3 +21,7 @@
 Running test_gsm0503_tch_afhs_decode_dtx(at offset=464): testing detection/decoding of AHS_SID_UPDATE
  ==> gsm0503_tch_ahs_decode_dtx() yields 'AHS_SID_UPDATE_CN (audio)' (rc=5, BER 106/212)
  ====> tch_data[] = { 6003ccb270 }
+Running test_gsm0503_tch_afhs_decode_dtx(at offset=0): testing tagging of FACCH/F
+ ==> gsm0503_tch_afs_decode_dtx() yields 'AMR_OTHER (audio)' (rc=-1, BER 456/456)
+Running test_gsm0503_tch_afhs_decode_dtx(at offset=0): testing tagging of FACCH/H
+ ==> gsm0503_tch_ahs_decode_dtx() yields 'AMR_OTHER (audio)' (rc=-1, BER 456/456)