Fixes samples Teapot/MoreTeapots armeabi-v7a-hard; native-audio debug build

Fixes two issues:
1. Remove redundant check for hard-float in Teapot/MoreTeapots and ndk_helper
   they depend.  The ndk-build system add those flags already for armeabi-v7a-hard
2. native-audio in debug build: assert on the non-existance var

Change-Id: Id6b2d38a264c2f2d0e0c7fe625991fcee1762800

ndk/platforms/android-9/samples/native-audio/jni/native-audio-jni.c

@@ -133,7 +133,7 @@ void bqPlayerCallback(SLAndroidSimpleBufferQueueItf bq, void *context)
 // this callback handler is called every time a buffer finishes recording
 void bqRecorderCallback(SLAndroidSimpleBufferQueueItf bq, void *context)
 {
-    assert(bq == bqRecorderBufferQueue);
+    assert(bq == recorderBufferQueue);
     assert(NULL == context);
     // for streaming recording, here we would call Enqueue to give recorder the next buffer to fill
     // but instead, this is a one-time buffer so we stop recording