Make test_options.timeout an int64

I forgot we supported integer properties, use an integer instead
of a string for test_options.timeout.

Test: m checkbuild
Change-Id: I22d3135b31ec93d15b530c430b9e9cda6dd3f416
diff --git a/java/robolectric.go b/java/robolectric.go
index 26f1e9d..b87ee0d 100644
--- a/java/robolectric.go
+++ b/java/robolectric.go
@@ -39,7 +39,7 @@
 
 	Test_options struct {
 		// Timeout in seconds when running the tests.
-		Timeout *string
+		Timeout *int64
 	}
 }