Drop invalid DCHECK, hashes can be 0

Bug: chromiume:733118
Change-Id: Ic144342d86fc84bf5c4700cec357ac8f3c6b2cb3
Reviewed-on: https://chromium-review.googlesource.com/535522Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45953}

src/objects/hash-table.h

@@ -263,10 +263,7 @@ class HashTableKey {
   // Required.
   virtual ~HashTableKey() {}
 
-  uint32_t Hash() const {
-    DCHECK_NE(0, hash_);
-    return hash_;
-  }
+  uint32_t Hash() const { return hash_; }
 
  protected:
   void set_hash(uint32_t hash) {