Rollup merge of #68575 - Wind-River:master_2020, r=alexcrichton
Rollup merge of #68575 - Wind-River:master_2020, r=alexcrichton

Disable the testcase for Vxworks.

r? @alexcrichton

graydon/rust,graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust,aidancully/rust