Ensure org.apache.geronimo.specs are excluded from tests

When we are compiling the compatibility test suite, the geronimo-jta_1.1_spec library could come transitively from different dependencies. Some of those dependencies are using wildcards to exclude it.

Since there is a bug in maven enforcer plugin MENFORCER-302 for the Dependency Convergence rule, when we are creating the product branches; the enforcer plugin finds (due to its bug) a productized version of geronimo-jta_1.1_spec and the transitive dependencies coming from the compatibility test suite, failing in that case.

As a workaround to avoid this problem, we need to add explicitly the exclusions of geronimo-jta_1.1_spec in the compatibility test suite.