Add the system image test to the bazel sandwich

Also make -test.sh files executable, while we wait for a bazel update
that will tell us which FileWrite actions should be executable.

Bug: 297268692
Test: m bazel_sandwich
Change-Id: I60498577ba12813bff8bbdbc1b997ea4addefd17
diff --git a/android/allowlists/allowlists.go b/android/allowlists/allowlists.go
index fec2cdc..75f2c3f 100644
--- a/android/allowlists/allowlists.go
+++ b/android/allowlists/allowlists.go
@@ -1645,5 +1645,9 @@
 			Label: "//build/bazel/examples/partitions:system_image",
 			Host:  false,
 		},
+		{
+			Label: "//build/bazel/examples/partitions:run_test",
+			Host:  false,
+		},
 	}
 )