Widen leak suppression for Extension::Create() to cover rb_tree nodes in Manifest.

tools/valgrind/memcheck/suppressions.txt

 # There are four kinds of suppressions in this file.
 # 1. third party stuff we have no control over
 #
 # 2. intentional unit test errors, or stuff that is somehow a false positive
 # in our own code, or stuff that is so trivial it's not worth fixing
 #
 # 3. Suppressions for real chromium bugs that are not yet fixed.
 # These should all be in chromium's bug tracking system (but a few aren't yet).
 # Periodically we should sweep this file and the bug tracker clean by
 # running overnight and removing outdated bugs/suppressions.
@@ skipping 5314 matching lines @@
 {
    bug_106326
    Memcheck:Uninitialized
    fun:_ZN15tracked_objects9DeathData11RecordDeathEiii
    fun:_ZN15tracked_objects10ThreadData11TallyADeathERKNS_6BirthsEii
    fun:_ZN15tracked_objects10ThreadData31TallyRunOnNamedThreadIfTrackingERKN4base12TrackingInfoERKNS_11TrackedTimeES7_
 }
 {
    bug_106331
    Memcheck:Leak
-   fun:_Znw*
+   ...
    fun:_ZN9Extension6CreateERK8FilePathNS_8LocationERKN4base15DictionaryValueEiPSs
 }
 
 #-----------------------------------------------------------------------
 # 4. These only occur on our Google workstations
 {
    bug_todo_freeres
    Memcheck:Free
    fun:free
    fun:__libc_freeres
@@ skipping 19 matching lines @@
    obj:/lib/libselinux.so.1
    obj:/lib/libselinux.so.1
 }
 {
    bug_todo_grep
    Memcheck:Leak
    fun:malloc
    obj:/bin/grep
    obj:/bin/grep
 }