sapi: Add <rtems/test.h>

Provide support functions to print the begin/end of test message.
Provide a test fatal extension to print out profiling reports in the
future.
tests/samples: Use <rtems/test.h>
tests/smptests: Use <rtems/test.h>
tests/fstests: Use <rtems/test.h>
score: Use only next field for chain on/off

It is sufficient to use one field for the chain on/off indication.  The
chain API functions are highly performance critical.