perf test: Display number of active running tests

perf test: Display number of active running tests

Before polling or sleeping to wait for a test to complete, print out
": Running (<num> active)" where the number of active tests is
determined by iterating over the tests and seeing which return false
for check_if_command_finished. The line erasing and printing out only
occur if the number of runnings tests changes to avoid the line
flickering excessively. Knowing tests are running allows a user to
know a test is running and in parallel mode how many of the tests are
waiting to complete. If color mode is disabled then avoid displaying
the "Running" message as deleting the line isn't reliable.

Tested-by: James Clark <james.clark@linaro.org>
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Colin Ian King <colin.i.king@gmail.com>
Cc: Howard Chu <howardchu95@gmail.com>
Cc: Weilin Wang <weilin.wang@intel.com>
Cc: Ilya Leoshkevich <iii@linux.ibm.com>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Dapeng Mi <dapeng1.mi@linux.intel.com>
Cc: Athira Jajeev <atrajeev@linux.vnet.ibm.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Veronika Molnarova <vmolnaro@redhat.com>
Link: https://lore.kernel.org/r/20241025192109.132482-3-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>