Disable dynamic superblock size when resize is on.
Disable dynamic superblock size when resize is on.

When resize is on, cm->width/height changes between calls to
select_sb_size(). So, we disable this speed feature.

BUG=aomedia:1933

Change-Id: Idc2952a400a2a7886954ac6bcc78e4eb09d935a7

GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom