Test mjsunit/string-indexof times out on ARM simulator

Removal of string slices made this test time out on the ARM simulator. Temporaly mark this as pass or timeout.

BUG=http://code.google.com/p/v8/issues/detail?id=500
TBR=christian.plesner.hansen@gmail.com
Review URL: http://codereview.chromium.org/390002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3264 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

test/mjsunit/mjsunit.status

@@ -61,3 +61,7 @@ string-compare-alignment: PASS || FAIL
 
 # Times out often in release mode on ARM.
 array-splice: PASS || TIMEOUT
+
+# Issue 500
+string-indexof: PASS || TIMEOUT
+