edge-testnet - add detection for ICMP packet block cases

If we have 100% packet loss on www.google.com we can assume
ICMP has been blocked.

.github/workflows/pr-checker.yml

@@ -6,7 +6,7 @@ concurrency:
   group: pe-utils-'${{ github.workflow }} @ ${{ github.event.pull_request.head.label || github.head_ref || github.ref }}'
   cancel-in-progress: true
 jobs:
-  run-shellcheck:
+  run-shellcheck-and-scripts:
     runs-on: ubuntu-22.04
     steps:
       - uses: actions/checkout@v3
@@ -15,9 +15,6 @@ jobs:
         run: shellcheck fw-tools/edge-testnet
       - name: Run edge-testnet
         run: | 
-          ping -h | true
-          ping -q -c 1 bootstrap.us-east-1.mbedcloud.com
-          ping -q -c 1 lwm2m.us-east-1.mbedcloud.com
           fw-tools/edge-testnet -e
       - run: shellcheck edge-info/edge-info
       - run: cat /etc/os-release

CHANGELOG.md

@@ -3,6 +3,7 @@
 1. [fw-tools] - Check return code of `openssl` calls. 
 1. [fw-tools] - Return non-zero exit code if any failures spotted.
 1. [fw-tools] - Skip L4 / netcat tests if BusyBox `nc` is detected (as it does not support DNS queries).
+1. [fw-tools] - Skip L3 / ping tests if 100% packet loss encountered with google.com. ICMP traffic is then most likely blocked.
 
 ## Izuma Edge utilities 2.3.2
 1. [fw-tools] - add `tcp-lwm2m.mbedcloud.com` address to be tested.

fw-tools/edge-testnet

@@ -291,7 +291,12 @@ test_L4() {
 }
 
 main() {
-    test_L3
+    pinggoogle=$(ping -q -c 1 google.com 2>&1)
+    if [[ "$pinggoogle" =~ "100% packet loss" ]]; then
+        echo "ICMP traffic blocked, skipping L3 (ping) tests."
+    else
+        test_L3
+    fi
     busyboxnc=$(nc 2>&1)
     if [[ "$busyboxnc" =~ "BusyBox" ]]; then
         echo "BusyBox netcat detected, skipping Layer 4 tests"