Add test to verify extensions in non-bean archives are loaded

Add a test to answers this question:

Does an extension have to be in an bean archive in order to be loaded?

Section 11.5 states:

"An extension is a service provider of the service javax.enterprise.inject.spi.Extension declared in META-INF/services."

If one assumes that "service provider" refers to the term defined in the jar specification [1], then one would conclude that an extension does not have to be in a bean archive to be recognized (these are orthogonal concerns).

A test for this scenario is available in the OpenTCK project and may be ported to the CDI TCK. [2]

[1] http://download.oracle.com/javase/6/docs/technotes/guides/jar/jar.html#Service%20Provider
[2] https://github.com/opentck/javaee_cdi/tree/master/src/test/java/org/opentck/javaee/cdi/spi/beforebeandiscovery