ext: Fix the MakeFixture setup

It was simply using an invalid log_call helper

JIRA: https://gem5.atlassian.net/projects/GEM5/issues/GEM5-533

Change-Id: I644b1c902a81a27beb6385690d2e43baf4c0919b
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/30218
Maintainer: Bobby R. Bruce <bbruce@ucdavis.edu>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Hoa Nguyen <hoanguyen@ucdavis.edu>

tests/gem5/fixture.py

@@ -191,7 +191,7 @@ class MakeFixture(Fixture):
         targets = set(self.required_by)
         command = ['make', '-C', self.directory]
         command.extend([target.target for target in targets])
-        log_call(command)
+        log_call(log.test_log, command, stderr=sys.stderr)
 
 
 class MakeTarget(Fixture):