Remove an unreachable leak filter.

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 # running overnight and removing outdated bugs/suppressions.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 1805 matching lines @@
    fun:_ZN22ChromeBrowserMainParts21PreMainMessageLoopRunEv
    fun:_ZN7content15BrowserMainLoop13CreateThreadsEv
    fun:_ZN7content21BrowserMainRunnerImpl10InitializeERKNS_18MainFunctionParamsE
    fun:_ZN7content11BrowserMainERKNS_18MainFunctionParamsE
    fun:_ZN7content23RunNamedProcessTypeMainERKSsRKNS_18MainFunctionParamsEPNS_19ContentMainDelegateE
    fun:_ZN7content21ContentMainRunnerImpl3RunEv
    fun:_ZN7content11ContentMainEiPPKcPNS_19ContentMainDelegateE
    fun:ChromeMain
 }
 {
-   bug_164178
-   Memcheck:Leak
-   fun:_Znw*
-   fun:_ZN3net25MultiThreadedCertVerifier6VerifyEPNS_15X509CertificateERKSsiPNS_6CRLSetEPNS_16CertVerifyResultERKN4base8CallbackIFviEEEPPvRKNS_11BoundNetLogE
-   fun:_ZN3net25SingleRequestCertVerifier6VerifyEPNS_15X509CertificateERKSsiPNS_6CRLSetEPNS_16CertVerifyResultERKN4base8CallbackIFviEEERKNS_11BoundNetLogE
-   fun:_ZN3net18SSLClientSocketNSS12DoVerifyCertEi
-   fun:_ZN3net18SSLClientSocketNSS15DoHandshakeLoopEi
-   fun:_ZN3net18SSLClientSocketNSS21OnHandshakeIOCompleteEi
-}
-{
    bug_164179
    Memcheck:Leak
    fun:_Znw*
    ...
    fun:_ZN3net10URLFetcher6CreateERK4GURLNS0_11RequestTypeEPNS_18URLFetcherDelegateE
    fun:_ZN18WebResourceService10StartFetchEv
 }
 {
    bug_166819
    Memcheck:Leak
@@ skipping 1799 matching lines @@
    Memcheck:Leak
    fun:malloc
    fun:_ZN3WTF9BitVector13OutOfLineBits6createEm
    fun:_ZN3WTF9BitVector15resizeOutOfLineEm
    fun:_ZN3WTF9BitVector10ensureSizeEm
    fun:_ZN3WTF9BitVectorC2Em
    fun:_ZN5blink10UseCounter9CountBitsC2Ev
    fun:_ZN5blink10UseCounterC1Ev
    fun:_ZN5blink4PageC1ERNS0_11PageClientsE
 }