aaudio: add thread safety annotation

Also improve naming to clarify lock requirements.

And call some locked methods that were not called before.
Although they were protected with a different lock so
it should have no effect.

Bug: 171296283
Test: adb logcat *:F
Test: In another window:
Test: atest AAudioTestCases
Change-Id: I6e863cbdea9250188e3f4b8f8654ef71c8951e74
diff --git a/media/libaaudio/src/Android.bp b/media/libaaudio/src/Android.bp
index 328ceda..aafcccc 100644
--- a/media/libaaudio/src/Android.bp
+++ b/media/libaaudio/src/Android.bp
@@ -21,6 +21,7 @@
     ],
 
     cflags: [
+        "-Wthread-safety",
         "-Wno-unused-parameter",
         "-Wall",
         "-Werror",