Remove "exit status" from run-test stdout.

This is left over from bash.

The python script already specifies the expected_exit_code,
so the stdout line is redundant and confusing (since the
process never actually printed such message to stdout).

The python runner will still abort if the test's exit code
does not match the declared expected value.

Test: test.py -r --all-target --optimizing --64
Change-Id: I69555bf959337fde362108f4df0524d66daddd14
8 files changed