scylla_docker: ignore comma in parsing result
scylla_docker: ignore comma in parsing result

Tests failed due error on parsing output:
   Op rate                   :   18,589 op/s  [READ: 18,589 op/s]
   Partition rate            :   18,589 pk/s  [READ: 18,589 pk/s]

with exception
   ERROR| Failed parsing stress results: Op rate:   11,779 op/s  [WRITE: 11,779 op/s], error: invalid literal for float(): 11,779
   Adding code to cut the ',' from parsed value.

Signed-off-by: Alex bykov <ec2c6fc53432402929a1744dcd109d6115118618@scylladb.com>
Signed-off-by: Amos Kong <eb01d8f828a6c9a20be4534e72e049aaf41503df@scylladb.com>

scylladb/scylla-artifact-tests,scylladb/scylla-artifact-tests