[TESTBUG] Allow for tier 1 like testing in OpenJDK 8u

In JDK 11+ there are nice targets for performing sanity checks via running a set of jtreg tests on a patch OpenJDK build:

Example:

$ make test-tier1

There is no equivalent target for OpenJDK 8u but it would be good to have as it gives developers a base line set of tests which should always pass prior check-in of the patch.