perf inject: Remove static variables

perf inject: Remove static variables

We want to reduce the impact that each of the builtins has on perf as a
whole, so use the superclassing of perf_tool mechanizm to move its
config knobs to the stack, so that only if we use that tool, its impact
will be felt.

In this case is more about consistency, as the impact of this tool is
minimal.

Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-z2b3matvawihtenmez9hkcja@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>