Remove extraneous tests from shared-vpc
Remove extraneous tests from shared-vpc

The shared-vpc integration tests duplicated instance and firewall tests
in the 'forseti' control, and were generalized across all forseti
firewall rules in a given project rather than firewall rules related to
the installation under test. This commit removes the duplicated tests.

forseti-security/terraform-google-forseti,forseti-security/terraform-google-forseti,forseti-security/terraform-google-forseti