dpdk: testpmd check packet drops

[mcgov]

Gathers and checks packet drops at the end of send receive tests. Senders are allowed to drop more packets, we intentionally tune it to maximize the PPS, so some drops are expected. The rough metric in this PR is that the percentage of packets dropped should not exceed 20% on the sender and 1% on the receiver.

[Copilot]

Pull request overview

This PR adds packet drop validation to DPDK send/receive tests by collecting and checking packet drop statistics at the end of test runs. The implementation introduces new regex patterns to capture packet drop and total packet counts from testpmd output, adds validation methods to ensure drop rates remain within acceptable thresholds (33% for sender, 1% for receiver), and annotates test results with receiver packet drop rates for monitoring purposes.

Key Changes:

• Added packet drop rate validation with configurable thresholds for sender and receiver
• Introduced new testpmd output parsing for packet drop metrics
• Enhanced test result annotations with packet drop statistics

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 5 comments.

File	Description
lisa/microsoft/testsuites/dpdk/dpdktestpmd.py	Added regex patterns for packet drop/total metrics, implemented check_tx_packet_drops() and check_rx_packet_drops() validation methods, extended populate_performance_data() to collect drop statistics
lisa/microsoft/testsuites/dpdk/dpdkutil.py	Integrated packet drop checks into verify_dpdk_send_receive() workflow, added annotate_packet_drops() helper function to record receiver drop rates in test results

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[LiliDeng]

@mcgov the description 20% is inconsistent with the changed code, is it expected? Please rebase code from the latest main.