When a valid data pointer is given make sure the size is greater than
zero.
A previous check for vp9 was incorrectly removed in:
7050074 Make the api behavior conform to api spec.
No semantics for valid pointers + 0-sized frames are defined for VPx
codecs, so move the check to vpx_codec_decode(). This avoids an assert
in vp9.
+ add some basic invalid param testing for decoder init/decode/destroy
Change-Id: I99f9cef6076d15874fd72ac973f2685d8a2353c3
