[fuchsia-test-runner] Remove runner logs from stdout and stderr

Many tests use stdout and stderr to validate whether the test emitted
the correct output. Because fuchsia-test-runner.py was sending all
logs, including test output, to stdout, tests could not validate
output properly.

This change removes the runner logs from stdout and stderr entirely
with the exception of output from the test. All runner logs are still
available in the "log" file.

Fixed: https://fxbug.dev/351356417

Author: c6c7

src/ci/docker/scripts/fuchsia-test-runner.py

@@ -271,13 +271,6 @@ def setup_logging(self, log_to_file=False):
             logfile_handler.setLevel(logging.DEBUG)
             logfile_handler.setFormatter(fs)
             logging.getLogger().addHandler(logfile_handler)
-        stream_handler = logging.StreamHandler(sys.stdout)
-        stream_handler.setFormatter(fs)
-        if self.verbose:
-            stream_handler.setLevel(logging.DEBUG)
-        else:
-            stream_handler.setLevel(logging.INFO)
-        logging.getLogger().addHandler(stream_handler)
         logging.getLogger().setLevel(logging.DEBUG)
 
     @property
@@ -927,15 +920,15 @@ def run(self, args):
                 )
             else:
                 with open(stdout_path, encoding="utf-8", errors="ignore") as f:
-                    runner_logger.info(f.read())
+                    sys.stdout.write(f.read())
         if stderr_path is not None:
             if not os.path.exists(stderr_path):
                 runner_logger.error(
                     f"stderr file {stderr_path} does not exist."
                 )
             else:
                 with open(stderr_path, encoding="utf-8", errors="ignore") as f:
-                    runner_logger.error(f.read())
+                    sys.stderr.write(f.read())
 
         runner_logger.info("Done!")
         return return_code