Fix #7126 - saferepr for bytes params

bytes parametrize parameters cause error when --setup-show is used
and Python is called with -bb flag

src/_pytest/setuponly.py

@@ -1,4 +1,5 @@
 import pytest
+from _pytest._io.saferepr import saferepr
 
 
 def pytest_addoption(parser):
@@ -66,7 +67,11 @@ def _show_fixture_action(fixturedef, msg):
             tw.write(" (fixtures used: {})".format(", ".join(deps)))
 
     if hasattr(fixturedef, "cached_param"):
-        tw.write("[{}]".format(fixturedef.cached_param))
+        if isinstance(fixturedef.cached_param, bytes):
+            param = saferepr(fixturedef.cached_param, maxsize=42)
+        else:
+            param = fixturedef.cached_param
+        tw.write("[{}]".format(param))
 
     tw.flush()