X87: [crankshaft] Loads and stores to typed arrays have to reference the backing store holder.

  port 086d4598 (r32644)

  original commit message:
  The backing store is only held alive indirectly via the array buffer
  referenced by the holder (typed array), so it's not enough to keep the
  elements alive (or even just the external pointer loaded from the
  elements).

BUG=

Review URL: https://codereview.chromium.org/1503943002

Cr-Commit-Position: refs/heads/master@{#32648}

src/crankshaft/x87/lithium-x87.h

@@ -2155,7 +2155,7 @@ class LStoreKeyed final : public LTemplateInstruction<0, 4, 0> {
     inputs_[0] = obj;
     inputs_[1] = key;
     inputs_[2] = val;
-    inputs_[3] = backing_store_owner
+    inputs_[3] = backing_store_owner;
   }
 
   bool is_fixed_typed_array() const {