tests: Create base classes to encapsulate common test configurations

tests: Create base classes to encapsulate common test configurations

Most of the test cases currently contain a large amount of duplicated
boiler plate code. This changeset introduces a set of classes that
encapsulates most of the functionality when setting up a test
configuration.

The following base classes are introduced:
* BaseSystem - Basic system configuration that can be used for both
               SE and FS simulation.

* BaseFSSystem - Basic FS configuration uni-processor and multi-processor
                 configurations.

* BaseFSSystemUniprocessor - Basic FS configuration for uni-processor
                             configurations. This is provided as a way
			     to make existing test cases backwards
			     compatible.

Architecture specific implementations are provided for ARM, Alpha, and
X86.