Move StagedRollbackTest from postsubmit to presubmit

Bug: 324596460
Change-Id: Iad7bfd7cb56f0c16366a9aa61b9466545ee4c661
diff --git a/libprocessgroup/TEST_MAPPING b/libprocessgroup/TEST_MAPPING
index 29a9ff0..b713f6b 100644
--- a/libprocessgroup/TEST_MAPPING
+++ b/libprocessgroup/TEST_MAPPING
@@ -1,5 +1,5 @@
 {
-  "postsubmit": [
+  "presubmit": [
     {
       "name": "StagedRollbackTest"
     }