edge/test: Rename test_rlc_decoder to test_rlc_unit_decoder

This test only covers RLC data units and not whole RLC messages.

Sponsored-by: On-Waves ehf
diff --git a/tests/edge/EdgeTest.ok b/tests/edge/EdgeTest.ok
index 6597f07..791f0d5 100644
--- a/tests/edge/EdgeTest.ok
+++ b/tests/edge/EdgeTest.ok
@@ -1,4 +1,4 @@
 === start test_coding_scheme ===
 === end test_coding_scheme ===
-=== start test_rlc_decoder ===
-=== end test_rlc_decoder ===
+=== start test_rlc_unit_decoder ===
+=== end test_rlc_unit_decoder ===