error check vp9 superframe parsing

This patch insures that the last byte of a chunk that contains a
valid superframe marker byte,  actually has a proper superframe index.
If not it returns an error.

As part of doing that the file : vp90-2-15-fuzz-flicker.webm now fails
to decode properly and moves to the invalid file test from the test
vector suite.

Change-Id: I5f1da7eb37282ec0c6394df5c73251a2df9c1744

test/test.mk

diff --git a/test/test.mk b/test/test.mk
index 5d02d66..7a3eaa9 100644
--- a/test/test.mk
+++ b/test/test.mk
@@ -763,6 +763,8 @@
 # Invalid files for testing libvpx error checking.
 LIBVPX_TEST_DATA-$(CONFIG_VP9_DECODER) += invalid-vp90-01.webm
 LIBVPX_TEST_DATA-$(CONFIG_VP9_DECODER) += invalid-vp90-01.webm.res
+LIBVPX_TEST_DATA-$(CONFIG_VP9_DECODER) += invalid-vp90-02.webm
+LIBVPX_TEST_DATA-$(CONFIG_VP9_DECODER) += invalid-vp90-02.webm.res
 
 ifeq ($(CONFIG_DECODE_PERF_TESTS),yes)
 # BBB VP9 streams