Introduce non-portable SPI mode

The spec contains statements like these:

Throws:
java.lang.IllegalStateException - if called during application initialization, before the AfterDeploymentValidation event is fired The container is permitted to define a non-portable mode in which getBeans(String) may be called from an observer of the AfterBeanDiscovery event.

We need to implement the non-portable mode as otherwise some legacy extensions, e.g. Seam Solder do not work properly. The mode should be activated by a system properly (the name to be defined). In this mode the checks on BeanManager methods will be less strict.

It should be verified that SOLDER-339 does not occur with the non-portable mode.