Remove AAudioTesting.h from headers to be exported to NDK

but include the associated names in the global symbol export list, so
that apps that receive AAudioTesting.h outside of NDK can access the
symbols without dlsym().

Test: builds OK
Change-Id: If68f35145d68f359ebb7995ffcf9c9b8f9be6eb1
diff --git a/media/libaaudio/Android.bp b/media/libaaudio/Android.bp
index f539ba9..6e60f24 100644
--- a/media/libaaudio/Android.bp
+++ b/media/libaaudio/Android.bp
@@ -16,12 +16,14 @@
     name: "libAAudio_headers",
     from: "include",
     to: "",
-    srcs: ["include/aaudio/*.h"],
+    // omit AAudioTesting.h; supplied separately to those who need it
+    srcs: ["include/aaudio/AAudio.h"],
     license: "include/aaudio/NOTICE",
 }
 
 ndk_library {
     name: "libaaudio",
+    // deliberately includes symbols from AAudioTesting.h
     symbol_file: "libaaudio.map.txt",
     first_version: "26",
     unversioned_until: "current",