Add belated test for the SeqStringSetChar bug.

test/mjsunit/regress/regress-seqstrsetchar-ex3.js

Index: test/mjsunit/regress/regress-seqstrsetchar-ex3.js
diff --git a/test/mjsunit/elide-double-hole-check-7.js b/test/mjsunit/regress/regress-seqstrsetchar-ex3.js
similarity index 84%
copy from test/mjsunit/elide-double-hole-check-7.js
copy to test/mjsunit/regress/regress-seqstrsetchar-ex3.js
index 2b13aff881589d79051a23819415be3fa22eee30..e2592a1615aa6bcfbbaa688319b8a0f6d34aa4a7 100644
--- a/test/mjsunit/elide-double-hole-check-7.js
+++ b/test/mjsunit/regress/regress-seqstrsetchar-ex3.js
@@ -27,14 +27,19 @@
 
 // Flags: --allow-natives-syntax
 
-function f1(a, i) {
-  return a[i] + 0.5;
+function test() {
+  var string = %NewString(10, true);
+  for (var i = 0; i < 10; i++) {
+    %_OneByteSeqStringSetChar(string, i, 65);
+    %_OneByteSeqStringSetChar(string, i, 66);
+  }
+  for (var i = 0; i < 10; i++) {
+    assertEquals("B", string[i]);
+  }
 }
-var arr = [0.0,,2.5];
-assertEquals(0.5, f1(arr, 0));
-assertEquals(0.5, f1(arr, 0));
-Array.prototype.__proto__[1] = 1.5;
-assertEquals(2, f1(arr, 1));
-%OptimizeFunctionOnNextCall(f1);
-assertEquals(2, f1(arr, 1));
-assertEquals(0.5, f1(arr, 0));
+
+test();
+test();
+%OptimizeFunctionOnNextCall(test);
+test();
+