[GR-75506] Remove hardcoded tox PyPI mirror

Author: timfel

graalpython/com.oracle.graal.python.test/src/tox/leftpad/tox.ini

@@ -9,7 +9,12 @@ commands =
 
 [testenv:graalpy]
 basepython=graalpy
-setenv=
-  PIP_INDEX_URL=https://ol-graal.oraclecorp.com/nexus-cache/repository/pypi-proxy/simple/
-  PIP_TRUSTED_HOST=ol-graal.oraclecorp.com
-passenv = GRAALPY_LEFTPAD_FAIL,GRAAL_PYTHON_ARGS,GRAAL_PYTHON_VM_ARGS
+passenv =
+  GRAALPY_LEFTPAD_FAIL
+  GRAAL_PYTHON_ARGS
+  GRAAL_PYTHON_VM_ARGS
+  PIP_EXTRA_INDEX_URL
+  PIP_INDEX_URL
+  PIP_RETRIES
+  PIP_TIMEOUT
+  PIP_TRUSTED_HOST