Add an argument that makes stem TRACE output log to a file
In #30591 (moved), there is too much TRACE output for the Travis console.
We can log to a file, and tail instead.
But it would be nice to still have the test progress on the console.
In #30591 (moved), there is too much TRACE output for the Travis console.
We can log to a file, and tail instead.
But it would be nice to still have the test progress on the console.