dev-python/tox: only depend on dev-python/regex for tests w/o pypy

Skip tests importing re_assert for pypy.

Bug: https://bugs.gentoo.org/924136
Signed-off-by: Sam James <sam@gentoo.org>

dev-python/tox/tox-4.12.1.ebuild

@@ -42,8 +42,8 @@ BDEPEND="
 		dev-python/psutil[${PYTHON_USEDEP}]
 		dev-python/pytest-mock[${PYTHON_USEDEP}]
 		dev-python/pytest-xdist[${PYTHON_USEDEP}]
-		dev-python/re-assert[${PYTHON_USEDEP}]
 		$(python_gen_cond_dep '
+			dev-python/re-assert[${PYTHON_USEDEP}]
 			dev-python/time-machine[${PYTHON_USEDEP}]
 		' 'python*')
 	)
@@ -83,5 +83,10 @@ python_test() {
 		'tests/tox_env/python/pip/test_pip_install.py::test_constrain_package_deps[requirements_constraints_indirect-True-True]'
 	)
 
+	[[ ${EPYTHON} == pypy3 ]] && EPYTEST_IGNORE+=(
+		# requires dev-python/re-assert
+		tests/session/cmd/test_sequential.py
+	)
+
 	epytest
 }