Temporarily disable AVxEncoderThreadLSTest
Temporarily disable AVxEncoderThreadLSTest

A recent set of changes braks this test in certain compiler
configurations. Let's disable until we get to the bottom of
the root cause.

Change-Id: I278622f1aa2a3f72ef90a846ec87619f094e73a0

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