[test] add testcase for GH #766, not repro anymore

this paniced with asan only. no need for an ok test here

t/pmc/resizablepmcarray.t

@@ -1,5 +1,5 @@
 #!./parrot
-# Copyright (C) 2001-2011, Parrot Foundation.
+# Copyright (C) 2001-2014, Parrot Foundation.
 
 =head1 NAME
 
@@ -958,6 +958,14 @@ too_low:
     finalize $P9
 too_low_end:
     ok($I0, "splice with negative offset too low")
+
+    # GH 766 heap-buffer-overflow with asan
+    $P1 = new ['ResizablePMCArray']
+    $P2 = new ['ResizablePMCArray']
+    $P1 = 2
+    $P2 = 0
+    splice $P1, $P2, 0, 1
+
 .end