Add property to prevent commit for Vts test

Old approach (do not start class main) does not work because when
testings userdebug GSI on user system, adb does not start until the
framework starts.

Bug: 134126407
Test: Test passes with userdebug GSI on user Taimen
Change-Id: I20441964dbc7b6ad5b445fa17a1374c1282bbbd8

Checkpoint.cpp

@@ -139,6 +139,11 @@ Status cp_commitChanges() {
     if (!isCheckpointing) {
         return Status::ok();
     }
+    if (android::base::GetProperty("persist.vold.dont_commit_checkpoint", "0") == "1") {
+        LOG(WARNING)
+            << "NOT COMMITTING CHECKPOINT BECAUSE persist.vold.dont_commit_checkpoint IS 1";
+        return Status::ok();
+    }
     sp<IBootControl> module = IBootControl::getService();
     if (module) {
         CommandResult cr;