Use mock ArrayBuffer allocator to avoid really allocating 1Gb.

test/mjsunit/regress/regress-319722-ArrayBuffer.js

Index: test/mjsunit/regress/regress-319722-ArrayBuffer.js
diff --git a/test/mjsunit/regress/regress-319722-ArrayBuffer.js b/test/mjsunit/regress/regress-319722-ArrayBuffer.js
index c8aed9e38cf7647836b68ce0428c98b7ba374d6d..1849bd2247a4750336b29e68b41bbb7d6ba2d1af 100644
--- a/test/mjsunit/regress/regress-319722-ArrayBuffer.js
+++ b/test/mjsunit/regress/regress-319722-ArrayBuffer.js
@@ -25,9 +25,20 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-// Flags: --nostress-opt --allow-natives-syntax
+// Flags: --nostress-opt --allow-natives-syntax --mock-arraybuffer-allocator
 var maxSize = %MaxSmi() + 1;
-var ab = new ArrayBuffer(maxSize);
+var ab;
+
+// Allocate the largest ArrayBuffer we can on this architecture.
+for (k = 8; k >= 1 && ab == null; k = k/2) {
+  try {
+    ab = new ArrayBuffer(maxSize * k);
+  } catch (e) {
+    ab = null;
+  }
+}
+
+assertTrue(ab != null);
 
 function TestArray(constr) {
   assertThrows(function() {