blockiness_test: fix implicit float conversion
blockiness_test: fix implicit float conversion

float->int as reported by -Wfloat-conversion

Change-Id: Icb0ecb9e2d54edb95813d9f2de34cb6c27b63cbd
(cherry picked from commit 5e2791b54da066cc8543c066813373c9274ff53f)

GrokImageCompression/aom,luctrudeau/aom,luctrudeau/aom,mbebenita/aom,mbebenita/aom,luctrudeau/aom,smarter/aom,mbebenita/aom,smarter/aom,GrokImageCompression/aom,luctrudeau/aom,GrokImageCompression/aom,mbebenita/aom,luctrudeau/aom,luctrudeau/aom,smarter/aom,mbebenita/aom,smarter/aom,GrokImageCompression/aom,smarter/aom,mbebenita/aom,smarter/aom,GrokImageCompression/aom,GrokImageCompression/aom,mbebenita/aom,mbebenita/aom,mbebenita/aom