Remove resolved TODO

As far as I understand the TODO, it has been resolved already some lines
below:

if (kEnableDebug) {
  VerifyCodeRangeIsDisjoint(data);
}

bug: v8:8015
R=titzer@chromium.org

Change-Id: I3686ad609b7c04e56b14ad2d1ccb265ac260bac7
Reviewed-on: https://chromium-review.googlesource.com/1185012Reviewed-by: Ben Titzer <titzer@chromium.org>
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55311}

src/trap-handler/handler-outside.cc

@@ -134,7 +134,6 @@ CodeProtectionInfo* CreateHandlerData(
 int RegisterHandlerData(
     Address base, size_t size, size_t num_protected_instructions,
     const ProtectedInstructionData* protected_instructions) {
-  // TODO(eholk): in debug builds, make sure this data isn't already registered.
 
   CodeProtectionInfo* data = CreateHandlerData(
       base, size, num_protected_instructions, protected_instructions);