audio: Add StreamWorker to aidl/common

This utility class has been copied from HIDL VTS.
It will be used both for the default implementation
and AIDL VTS, and might need modifications.

Bug: 205884982
Test: atest libaudioaidlcommon_test
Change-Id: I43b35b0c23ae45305dca66e15b60820cad19635e
diff --git a/audio/aidl/common/TEST_MAPPING b/audio/aidl/common/TEST_MAPPING
new file mode 100644
index 0000000..9dcf44e
--- /dev/null
+++ b/audio/aidl/common/TEST_MAPPING
@@ -0,0 +1,7 @@
+{
+  "presubmit": [
+    {
+      "name": "libaudioaidlcommon_test"
+    }
+  ]
+}