Compress pcap file before copying it from pft to sonic-mgmt (sonic-net#11391)

Before change, it took about 15 minutes to copy a 400M pcap file from ptf to sonic-mgmt.
After change, the 400M pcap file can be compressed to 4M, and the copy takes 2 seconds.

Author: weiguo-nvidia

tests/ptf_runner.py

@@ -21,8 +21,12 @@ def ptf_collect(host, log_file):
     pcap_file = filename_prefix + '.pcap'
     output = host.shell("[ -f {} ] && echo exist || echo null".format(pcap_file))['stdout']
     if output == 'exist':
-        filename_pcap = './logs/ptf_collect/' + rename_prefix + '.' + suffix + '.pcap'
-        host.fetch(src=pcap_file, dest=filename_pcap, flat=True, fail_on_missing=False)
+        # Compress the file
+        compressed_pcap_file = pcap_file + '.tar.gz'
+        host.archive(path=pcap_file, dest=compressed_pcap_file, format='gz')
+        # Copy compressed file from ptf to sonic-mgmt
+        filename_pcap = './logs/ptf_collect/' + rename_prefix + '.' + suffix + '.pcap.tar.gz'
+        host.fetch(src=compressed_pcap_file, dest=filename_pcap, flat=True, fail_on_missing=False)
         allure.attach.file(filename_pcap, 'ptf_pcap: ' + filename_pcap, allure.attachment_type.PCAP)