Moving feature checks code under tools/build directory.

Changing also $feature_dir to point to new feature directory location
and perf Makefiles to include Makefile.feature from new location.
Signed-off-by: NJiri Olsa <jolsa@kernel.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <david.ahern@oracle.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/tip-3lamtb30dhf4wo99y1n8kxg0@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

The various testcases used different styles, which was not really
visible as long as they hid in feature-tests.mak. Now that they
are out in the open make them prettier.

( Also delete the leftover, empty feature-tests.mak file. )

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-drDWk8xltndjdsespzjbhu6w@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-9wfutfb8ufFHrddrwlejqrai@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>