Fix ./run_tests.sh -V --virtual-env-name

Currently if --virtual-env-name is specified, the tests fail
because it still creates .venv/ but then looks in the specified
location to use the venv.

This makes --virtual-env-name work as expected.

Change-Id: I036cd08f7b7b9dc87e7012f8dd198a26375297a2
Merge "Fix ./run_tests.sh -V --virtual-env-name"