fix(tox): Use --dist=loadfile

Author: marioevz

tox.ini

@@ -48,7 +48,7 @@ commands =
 commands =
     pytest \
         -m "not slow" \
-        -n auto --maxprocesses 6 \
+        -n auto --maxprocesses 6 --dist=loadfile \
         --cov-config=pyproject.toml \
         --cov=ethereum \
         --cov-report=term \
@@ -98,7 +98,7 @@ passenv =
 commands =
     pytest \
         -m "not slow and not evm_tools" \
-        -n auto --maxprocesses 5 \
+        -n auto --maxprocesses 5 --dist=loadfile \
         --ignore-glob='tests/test_t8n.py' \
         --ignore-glob='eest_tests/*' \
         --basetemp="{temp_dir}/pytest" \