Create TEST_MAPPING file for transcoder presubmit tests

Bug: 173627260
Test: atest --include-subdir frameworks/av/media/libmediatranscoding\
      :presubmit
Change-Id: Ifd79f00f1331ffc6fc8aa35705153ad0f58b5650
diff --git a/media/libmediatranscoding/TEST_MAPPING b/media/libmediatranscoding/TEST_MAPPING
new file mode 100644
index 0000000..f8a9db9
--- /dev/null
+++ b/media/libmediatranscoding/TEST_MAPPING
@@ -0,0 +1,32 @@
+{
+    "presubmit": [
+        {
+            "name": "MediaSampleQueueTests"
+        },
+        {
+            "name": "MediaSampleReaderNDKTests"
+        },
+        {
+            "name": "MediaSampleWriterTests"
+        },
+        {
+            "name": "MediaTrackTranscoderTests"
+        },
+        {
+            "name": "MediaTranscoderTests"
+        },
+        {
+            "name": "PassthroughTrackTranscoderTests"
+        },
+        {
+            "name": "TranscodingClientManager_tests"
+        },
+        {
+            "name": "TranscodingSessionController_tests"
+        },
+        {
+            "name": "VideoTrackTranscoderTests"
+        }
+    ]
+}
+