In a test, I called print() on a multi-line string and saw the log
showing each line 0.2 seconds apart. redirect.stdout seems to be pretty
inefficient.
Instead, put a print() function into the testenv, to directly call log()
on the strings passed to print().
The initial idea for redirect_stdout was that we could print() in any
deeper functions called from a test script. But we have no such nested
print() anywhere, only in test scripts themselves.
As a result of this, a multi-line print() in test scripts now no longer
puts the log prefix (timestamp, test name...) and suffix (backtrace /
source position) to each single line, but prints the multiline block
between a single log prefix and suffix -- exactly like the log()
function does everywhere else.
I actually briefly implemented adding the log prefix to each separate
line everywhere, but decided that it is not a good idea: in some places
we log config file snippets and other lists, and prepending the log
prefix to each line makes pasting such a snippet from (say) a jenkins
log super cumbersome. And the log prefix (backtrace) attached on each
separate line makes multiline blocks very noisy, unreadable.
Change-Id: I0972c66b9165bd7f2b0b387e0335172849199193
3b493f3567