Revert of [serializer] add test case for unknown external references.

Revert of [serializer] add test case for unknown external references. (patchset #3 id:40001 of https://codereview.chromium.org/2428463002/ )

Reason for revert:
Blocks roll:
https://codereview.chromium.org/2428853002/

Original issue's description:
> [serializer] add test case for unknown external references.
> 
> Unknown external references must trigger assertion failure.
> 
> Committed: https://crrev.com/0655c45986eedfc2948d3b47ccac9ed57533e524
> Cr-Commit-Position: refs/heads/master@{#40391}

TBR=jochen@chromium.org,yangguo@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

[Michael Achenbach, 2016-10-18 13:23:33]

The CQ bit was checked by machenbach@chromium.org

[Michael Achenbach, 2016-10-18 13:23:34]

Created Revert of [serializer] add test case for unknown external references.

[commit-bot: I haz the power, 2016-10-18 13:23:38]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-10-18 13:23:41]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-10-18 13:23:42]

Failed to apply patch for src/snapshot/serializer-common.cc:
While running git apply --index -3 -p1;
  error: patch failed: src/snapshot/serializer-common.cc:7
  Falling back to three-way merge...
  Applied patch to 'src/snapshot/serializer-common.cc' with conflicts.
  U src/snapshot/serializer-common.cc

Patch:       src/snapshot/serializer-common.cc
Index: src/snapshot/serializer-common.cc
diff --git a/src/snapshot/serializer-common.cc
b/src/snapshot/serializer-common.cc
index
6c400cd25ea2c9dfe1cd08a0c6bdf486e2bc8666..baab8f3d6b26aca39cd98688b0d83def58ba0c0f
100644
--- a/src/snapshot/serializer-common.cc
+++ b/src/snapshot/serializer-common.cc
@@ -7,10 +7,6 @@
 #include "src/external-reference-table.h"
 #include "src/ic/stub-cache.h"
 #include "src/list-inl.h"
-
-#if defined(DEBUG) && defined(V8_OS_LINUX)
-#include <execinfo.h>
-#endif  // DEBUG && V8_OS_LINUX
 
 namespace v8 {
 namespace internal {
@@ -37,14 +33,7 @@
   DCHECK_NOT_NULL(address);
   base::HashMap::Entry* entry =
       const_cast<base::HashMap*>(map_)->Lookup(address, Hash(address));
-  if (entry == nullptr) {
-    void* function_addr = address;
-    v8::base::OS::PrintError("Unknown external reference %p.\n",
function_addr);
-#if defined(DEBUG) && defined(V8_OS_LINUX)
-    v8::base::OS::PrintError("%s\n", backtrace_symbols(&function_addr, 1)[0]);
-#endif  // DEBUG && V8_OS_LINUX
-    v8::base::OS::Abort();
-  }
+  DCHECK_NOT_NULL(entry);
   return static_cast<uint32_t>(reinterpret_cast<intptr_t>(entry->value));
 }

[Michael Achenbach, 2016-10-18 13:29:01]

Abandoning this in favor of the fix.