Remove duplicate suppression by reverting r54068.

tools/valgrind/memcheck/suppressions.txt

Index: tools/valgrind/memcheck/suppressions.txt
diff --git a/tools/valgrind/memcheck/suppressions.txt b/tools/valgrind/memcheck/suppressions.txt
index 98400f7d4d909d48f21eda6b6535f3e54698fa9e..cf441dce4304ca434becfd1f8e383c9daa9b624c 100644
--- a/tools/valgrind/memcheck/suppressions.txt
+++ b/tools/valgrind/memcheck/suppressions.txt
@@ -3591,18 +3591,6 @@
    fun:_ZN7Browser*ENS_4TypeEP7Profile
 }
 {
-   bug_50579
-   Memcheck:Leak
-   fun:_Znw*
-   fun:_ZN3net14DnsReloadTimer7ExpiredEv
-   fun:_ZN3net24DnsReloadTimerHasExpiredEv
-   fun:_ZN3net22SystemHostResolverProcERKSsNS_13AddressFamilyEiPNS_11AddressListEPi
-   fun:_ZN3net15ResolveAddrInfoEPNS_16HostResolverProcERKSsNS_13AddressFamilyEiPNS_11AddressListEPi
-   fun:_ZN3net16HostResolverImpl3Job8DoLookupEv
-   fun:_Z16DispatchToMethodIN3net16HostResolverImpl3JobEMS2_FvvEEvPT_T0_RK6Tuple0
-   fun:_ZN14RunnableMethodIN3net16HostResolverImpl3JobEMS2_FvvE6Tuple0E3RunEv
-}
-{
    bug_50583
    Memcheck:Leak
    fun:_Znw*