Update V8 to version 4.1.0.21

This is a cherry-pick of all commits up to and including the
4.1.0.21 cherry-pick in Chromium.

Original commit message:

Version 4.1.0.21 (cherry-pick)

Merged 206e9136bde0f2b5ae8cb77afbb1e7833e5bd412

Unlink pages from the space page list after evacuation.

BUG=430201
LOG=N
R=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/953813002

Cr-Commit-Position: refs/branch-heads/4.1@{#22}
Cr-Branched-From: 2e08d2a7aa9d65d269d8c57aba82eb38a8cb0a18-refs/heads/candidates@{#25353}

---

FPIIM-449

Change-Id: I8c23c7bbb70772b4858fe8a47b64fa97ee0d1f8c
diff --git a/test/webkit/testcfg.py b/test/webkit/testcfg.py
index e4e3f8f..aa81964 100644
--- a/test/webkit/testcfg.py
+++ b/test/webkit/testcfg.py
@@ -109,7 +109,11 @@
             string.startswith("tools/nacl-run.py") or
             string.find("BYPASSING ALL ACL CHECKS") > 0 or
             string.find("Native Client module will be loaded") > 0 or
-            string.find("NaClHostDescOpen:") > 0)
+            string.find("NaClHostDescOpen:") > 0 or
+            # FIXME(machenbach): The test driver shouldn't try to use slow
+            # asserts if they weren't compiled. This fails in optdebug=2.
+            string == "Warning: unknown flag --enable-slow-asserts." or
+            string == "Try --help for options")
 
   def IsFailureOutput(self, output, testpath):
     if super(WebkitTestSuite, self).IsFailureOutput(output, testpath):