tools/lib/lockdep/tests: Fix shellcheck warnings

tools/lib/lockdep/tests: Fix shellcheck warnings

Use find instead of ls to avoid splitting filenames that contain spaces.
Use rm -f instead of if ... then rm ...; fi. This patch addresses all
shellcheck complaints about the run_tests.sh shell script.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman Long <longman@redhat.com>
Cc: johannes.berg@intel.com
Cc: tj@kernel.org
Link: https://lkml.kernel.org/r/20181207011148.251812-3-bvanassche@acm.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>