Add one more suppression for [false?] memory leak reports in std::string

tools/valgrind/memcheck/suppressions.txt

 # There are three 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 # running overnight and removing outdated bugs/suppressions.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 622 matching lines @@
    fun:_ZNSs4_Rep9_S_createE*RKSaIcE
    fun:_ZNSs4_Rep8_M_cloneERKSaIcE*
 }
 {
    bug_76386c
    Memcheck:Leak
    fun:_Znw*
    fun:_ZNSs4_Rep9_S_createE*RKSaIcE
    fun:_ZNSs9_M_mutateEjjj
 }
+{
+   bug_76386d
+   Memcheck:Leak
+   fun:_Znw*
+   fun:_ZNSs4_Rep9_S_createEjjRKSaIcE
+   ...
+   fun:_ZNSsC1ERKSsjj
+}
 
 #-----------------------------------------------------------------------
 # 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
 
 # See tools/valgrind/memcheck_analyze.py before modifying sanity tests.
 {
    Memcheck sanity test 01 (memory leak).
    Memcheck:Leak
    fun:_Zna*
@@ skipping 4546 matching lines @@
    fun:_ZN3net22HttpNetworkTransaction6DoLoopEi
    fun:_ZN3net22HttpNetworkTransaction12OnIOCompleteEi
    fun:_ZN3net22HttpNetworkTransaction13OnStreamReadyERKNS_9SSLConfigERKNS_9ProxyInfoEPNS_10HttpStreamE
    fun:_ZN3net21HttpStreamFactoryImpl7Request13OnStreamReadyEPNS0_3JobERKNS_9SSLConfigERKNS_9ProxyInfoEPNS_10HttpStreamE
    fun:_ZN3net21HttpStreamFactoryImpl3Job21OnStreamReadyCallbackEv
    fun:_Z16DispatchToMethodIN3net21HttpStreamFactoryImpl3JobEMS2_FvvEEvPT_T0_RK6Tuple0
    fun:_ZN27ScopedRunnableMethodFactoryIN3net21HttpStreamFactoryImpl3JobEE14RunnableMethodIMS2_FvvE6Tuple0E3RunEv
    fun:_ZN4base6subtle18TaskClosureAdapter3RunEv
 }
 {
-   bug_92548
-   Memcheck:Leak
-   fun:_Znw*
-   ...
-   fun:_ZNSsC1ERKSsjj
-   fun:_ZNK4GURL15ComponentStringERKN9url_parse9ComponentE
-   fun:_ZNK4GURL4pathEv
-   fun:_ZN3net8HttpUtil14PathForRequestERK4GURL
-   fun:_ZN3net15HttpBasicStream11SendRequestERKNS_18HttpRequestHeadersEPNS_16UploadDataStreamEPNS_16HttpResponseInfoEP14CallbackRunnerI6Tuple1IiEE
-   fun:_ZN3net22HttpNetworkTransaction13DoSendRequestEv
-   fun:_ZN3net22HttpNetworkTransaction6DoLoopEi
-   fun:_ZN3net22HttpNetworkTransaction12OnIOCompleteEi
-   fun:_ZN3net22HttpNetworkTransaction13OnStreamReadyERKNS_9SSLConfigERKNS_9ProxyInfoEPNS_10HttpStreamE
-   fun:_ZN3net21HttpStreamFactoryImpl7Request13OnStreamReadyEPNS0_3JobERKNS_9SSLConfigERKNS_9ProxyInfoEPNS_10HttpStreamE
-   fun:_ZN3net21HttpStreamFactoryImpl3Job21OnStreamReadyCallbackEv
-   fun:_Z16DispatchToMethodIN3net21HttpStreamFactoryImpl3JobEMS2_FvvEEvPT_T0_RK6Tuple0
-   fun:_ZN27ScopedRunnableMethodFactoryIN3net21HttpStreamFactoryImpl3JobEE14RunnableMethodIMS2_FvvE6Tuple0E3RunEv
-   fun:_ZN4base6subtle18TaskClosureAdapter3RunEv
-}
-{
    bug_92571
    Memcheck:Leak
    fun:_Znw*
    fun:_ZN7history16TopSitesDatabase8CreateDBERK8FilePath
    fun:_ZN7history16TopSitesDatabase4InitERK8FilePath
    fun:_ZN7history15TopSitesBackend16InitDBOnDBThreadERK8FilePath
    fun:_Z16DispatchToMethodIN7history15TopSitesBackendEMS1_FvRK8FilePathES2_EvPT_T0_RK6Tuple1IT1_E
    fun:_ZN14RunnableMethodIN7history15TopSitesBackendEMS1_FvRK8FilePathE6Tuple1IS2_EE3RunEv
    fun:_ZN4base6subtle18TaskClosureAdapter3RunEv
 }
@@ skipping 133 matching lines @@
 }
 {
    bug_todo_getdelim2
    Memcheck:Leak
    fun:malloc
    fun:getdelim
    obj:/lib/libselinux.so.1
    obj:/lib/libselinux.so.1
    obj:/lib/libselinux.so.1
 }