Removes '/' prefix from gtest filter for parameterized tests. This prefix
was causing tests in fixtures like VKRenderGraphTestScheduler and
VKRenderGraphTestRender to be skipped in `make test`.
Only parameterized tests with an InstantiationName will have a '*/' in
their names as part of a prefix. But according to the spec, InstantiationName
is optional, and if not set it wont generate prefixes. In these cases, the
gtest_filter produced will not match the test names, and cause `make test`
to not run the tests.
Removing this '*/' prefix should still match any tests with a non-empty
InstantiationName.
Pull Request: https://projects.blender.org/blender/blender/pulls/136987