Skip reboot in GTest is isCollectOnly true

If we are simply collecting tests, skip reboots.

Test: unit tests
Bug: 112285471
Change-Id: Ia7d3df1b854bb1617535ac91051988b8e2fd712e
diff --git a/src/com/android/tradefed/testtype/GTest.java b/src/com/android/tradefed/testtype/GTest.java
index 33090ae..4c69085 100644
--- a/src/com/android/tradefed/testtype/GTest.java
+++ b/src/com/android/tradefed/testtype/GTest.java
@@ -226,7 +226,7 @@
                 testDevice.executeShellCommand(cmd);
             }
 
-            if (mRebootBeforeTest) {
+            if (mRebootBeforeTest && !isCollectTestsOnly()) {
                 CLog.d("Rebooting device before test starts as requested.");
                 testDevice.reboot();
             }