Disable adapt_scan by default

This experiment still requires review from AOMedia due to
conflicts with other adopted experiments.

Change-Id: I22c7ae3fd0aac7f537cabc6fc63218fb97851a7a

configure

@@ -476,7 +476,6 @@ post_process_cmdline() {
     done
 
     # Enable adopted experiments by default
-    soft_enable adapt_scan
     soft_enable ref_mv
     soft_enable cb4x4
     soft_enable filter_7bit