Fix JNI usage bugs.

Avoids calling other JNI stuff with a pending exception by
ensuring methods return after jniThrowException.

Bug: 137323248
Test: app in bug doesn't throw JNI DETECTED ERROR IN APPLICATION: JNI NewDirectByteBuffer called with pending exception java.lang.UnsupportedOperationException: Pixel format: 0x1 is unsupported
2

Change-Id: Id06cb476a02c4180881772708e3bb58511efe573
2 files changed