If the length of stdout exceeds 1 GB or if its memory allocation fails in
process_result(), set RESULT_STDOUT_MISSING. However, this failure must be
handled after we have retrieved all the outputs of the task. So don't return
with an app-level failure.
Change return type of process_available_results().
There is no necessity to return an integer since it handles failures and the
caller doesn't have to worry if it succeeded or failed.
Evict all output files of a task from remote cache on missing stdout or output
files.
Document what happens for stdout > 1 GB.
Add a message at the end of stdout to indicate it is truncated.