Use 'new' in all the snapshot reallocation functions instead of realloc.

runtime/platform/utils.h

Index: runtime/platform/utils.h
===================================================================
--- runtime/platform/utils.h	(revision 23633)
+++ runtime/platform/utils.h	(working copy)
@@ -171,6 +171,27 @@
            count <= (length - offset);
   }
 
+  template <class ElementType>
+  static inline ElementType* Realloc(ElementType* old_data,
+                                     intptr_t old_len,
+                                     intptr_t new_len) {
+    if ((old_len * sizeof(ElementType)) >
+        (new_len * sizeof(ElementType))) {
+      FATAL2("Realloc overflow: "
+             "'old_size'=%"Pd",'new_size'=%"Pd,
+             (old_len * sizeof(ElementType)),
+             (new_len * sizeof(ElementType)));
+    }
+    ElementType* new_data = new ElementType[new_len];
+    if (old_data != NULL) {
+      memmove(reinterpret_cast<void*>(new_data),
+              reinterpret_cast<void*>(old_data),
+              (old_len * sizeof(ElementType)));
+      delete[] old_data;
+    }
+    return new_data;
+  }
+
   // Utility functions for converting values from host endianess to
   // big or little endian values.
   static uint16_t HostToBigEndian16(uint16_t host_value);