Common demo tasks:

Common demo tasks:
- Add additional tests to GenQTest.c to test the updated priority inheritance mechanism.
- Slightly increase some delays in recmutex.c to prevent it reporting false errors in high load test cases.

SAMA5D3 Xplained IAR demo:
- Remove space being allocated for stacks that are not used.
- Remove explicit enabling of interrupts in ISR handers as this is now done from the central ISR callback before the individual handers are invoked.
- Reduce both the allocated heap size and the stack allocated to each task.
- Enable I cache.