bootloader_time should exclude time spent in ABL

It will only include time of pvmfw stage. ABL is being removed from
boot flow.

Bug: 240235424
Test: atest MicrodroidBenchmarks#testMicrodroidBootTime
Change-Id: I6cb1082de0015c25fa9c755fd6dd3b6a64be8d98
diff --git a/tests/helper/src/java/com/android/microdroid/test/device/MicrodroidDeviceTestBase.java b/tests/helper/src/java/com/android/microdroid/test/device/MicrodroidDeviceTestBase.java
index fdc846e..33de61c 100644
--- a/tests/helper/src/java/com/android/microdroid/test/device/MicrodroidDeviceTestBase.java
+++ b/tests/helper/src/java/com/android/microdroid/test/device/MicrodroidDeviceTestBase.java
@@ -276,7 +276,9 @@
         }
 
         private long getKernelStartedNanoTime() {
-            return kernelStartedNanoTime.getAsLong();
+            // pvmfw emits log at the end which is used to estimate the kernelStart time.
+            // In case of no pvmfw run(non-protected mode), use vCPU started time instead.
+            return kernelStartedNanoTime.orElse(vcpuStartedNanoTime.getAsLong());
         }
 
         private long getInitStartedNanoTime() {