Add a truncated WebP bitstream to test resources

This image has 1 less byte than the size mentioned in the RIFF header.

This corresponds to https://code.google.com/p/webp/issues/detail?id=185
and will be used to test the subsequent patch.

TBR=jzern

BUG=

Review URL: https://codereview.chromium.org/141653018

git-svn-id: svn://svn.chromium.org/blink/trunk@165576 bbb929c8-8fbe-4397-9dbb-9b2b20218538