net_test_bluetooth: adapter test refactor

Properly integrating net_test_bluetooth to utilize GUnit correctly.
Contains all the adapter tests and base class that all the other tests
utilize. Also removed all the old test code.

Bug: 25793348
Change-Id: Ie05d54e9d21f01e2d717bb79d187d7f0ff8a83f1
diff --git a/service/logging_helpers.cpp b/service/logging_helpers.cpp
index 4c00596..287a763 100644
--- a/service/logging_helpers.cpp
+++ b/service/logging_helpers.cpp
@@ -63,6 +63,15 @@
   }
 }
 
+const char *BtDiscoveryStateText(const bt_discovery_state_t state) {
+  switch (state) {
+    CASE_RETURN_TEXT(BT_DISCOVERY_STOPPED);
+    CASE_RETURN_TEXT(BT_DISCOVERY_STARTED);
+    default:
+      return "unknown discovery state code";
+  }
+}
+
 const char *BtScanModeText(const bt_scan_mode_t mode) {
   switch (mode) {
     CASE_RETURN_TEXT(BT_SCAN_MODE_NONE);