Integration harness: say when the install is over and the first boot is awaited

The wait loop printed "installing (Ns)" until SSH answered on the
installed system. A nightly run sat on that line for twelve minutes
while the install had finished after two: the first boot was what hung.

The firmware names what it starts on the serial port, so the loop now
notices the installed disk's Limine starting, logs how long the install
took, and counts the first boot from there.

test/integration.d/base-test.sh

@@ -535,7 +535,7 @@ install_phase() {
     -device usb-storage,drive=cidata
 
   log "Waiting for the unattended install to finish (timeout ${INSTALL_TIMEOUT}s)"
-  local waited=0 text progress_name
+  local waited=0 text progress_name first_boot_at=""
   while true; do
     # An unattended install reboots on its own; SSH answering means the
     # installed system is up (cidata's authorized_keys enables sshd).
@@ -576,7 +576,21 @@ install_phase() {
       printf -v progress_name 'success-install-progress-%04ds' "$waited"
       capture_console "$progress_name"
     fi
-    ((waited % 30 == 0)) && echo "    ... installing (${waited}s)"
+    # The firmware names what it starts on the serial port. Once that is the
+    # installed disk's Limine, the install is over and what is being waited
+    # for is the first boot: say so, or a hung first boot reads as a slow
+    # install.
+    if [[ -z $first_boot_at ]] && grep -aq 'starting Boot.*"Limine"' "$RUN_DIR/install-serial.log" 2>/dev/null; then
+      first_boot_at=$waited
+      log "Install finished after about ${waited}s. Waiting for the installed system's first boot."
+    fi
+    if ((waited % 30 == 0)); then
+      if [[ -n $first_boot_at ]]; then
+        echo "    ... first boot ($((waited - first_boot_at))s, install took about ${first_boot_at}s)"
+      else
+        echo "    ... installing (${waited}s)"
+      fi
+    fi
 
     sleep 10
     ((waited += 10))