binder: Move rustBinderTest to presubmit

rustBinderTest is no longer flaky on the test runners and should be run
on presubmit.

Bug: None
Test: atest -p frameworks/native/libs/binder/TEST_MAPPING
Change-Id: I5a426f483918470fa89ad44fbfded845e661af66
diff --git a/libs/binder/TEST_MAPPING b/libs/binder/TEST_MAPPING
index dafc879..1cfb560 100644
--- a/libs/binder/TEST_MAPPING
+++ b/libs/binder/TEST_MAPPING
@@ -53,9 +53,7 @@
     },
     {
       "name": "libbinder_rs-internal_test"
-    }
-  ],
-  "postsubmit": [
+    },
     {
       "name": "rustBinderTest"
     }