perf tools: Improve feature test debuggability

Certain feature tests fail with link errors:

  triton:~/tip/tools/perf/config/feature-checks> make test-libbabeltrace.bin
  gcc -MD  -o test-libbabeltrace.bin test-libbabeltrace.c # -lbabeltrace provided by
  /tmp/cc6dRSqd.o: In function `main':
  test-libbabeltrace.c:(.text+0xf): undefined reference to `bt_ctf_stream_class_get_packet_context_type'

although they should already fail with a build error due to lack of a
proper prototype for the function. Due to this I first tried to find
which library was missing - while it was the whole feature that was
missing from the .h file already.

To solve this, propagate -Wall -Werror to all testcases and remove them
from testcase Makefile rules that used them explicitly.

A missing feature now outputs:

  triton:~/tip/tools/perf/config/feature-checks> make test-libbabeltrace.bin
  gcc -MD  -Wall -Werror -o test-libbabeltrace.bin test-libbabeltrace.c  # -lbabeltrace provided by
  test-libbabeltrace.c: In function ‘main’:
  test-libbabeltrace.c:6:2: error: implicit declaration of function ‘bt_ctf_stream_class_get_packet_context_type’ [-Werror=implicit-function-declaration]

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: David Ahern <david.ahern@oracle.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20150228091627.GF31887@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>