Prune some old Valgrind suppressions.

The associated bug has been marked fixed for a long time. One of the
suppressions (bug_30704f) still fires, so we'll need to file
a separate issue for it.

BUG=30704
TBR=bruening@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/409793005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@284696 0039d316-1c4b-4281-b951-d872f2087c98

tools/valgrind/memcheck/suppressions.txt

@@ -769,59 +769,6 @@
    fun:zipCloseFileInZip
    fun:_Z*13AddEntryToZip*
 }
-{
-   bug_30704a
-   Memcheck:Uninitialized
-   fun:crc32
-   ...
-   fun:png_write_row
-}
-{
-   bug_30704b
-   Memcheck:Param
-   write(buf)
-   ...
-   fun:_ZN17SandboxedUnpacker17RewriteImageFilesEv
-}
-{
-   bug_30704c
-   Memcheck:Param
-   write(buf)
-   ...
-   fun:_ZNK16BrowserThemePack11WriteToDiskE*
-}
-{
-   bug_30704d
-   Memcheck:Uninitialized
-   ...
-   fun:png_process_data
-   fun:_ZN5blink14PNGImageReader6decodeERKNS_12SharedBufferEb
-   fun:_ZN5blink15PNGImageDecoder6decodeEb
-   fun:_ZN5blink15PNGImageDecoder18frameBufferAtIndexEm
-}
-{
-   bug_30704e
-   Memcheck:Uninitialized
-   obj:*/libpng*
-   fun:png_write_row
-}
-{
-   bug_30704f
-   Memcheck:Uninitialized
-   ...
-   fun:wk_png_write_find_filter
-   fun:wk_png_write_row
-}
-{
-   bug_30704g
-   Memcheck:Param
-   write(buf)
-   obj:*libpthread*
-   fun:_ZN9file_util19WriteFileDescriptorE*
-   fun:_ZN9file_util9WriteFileE*
-   fun:*SaveScreenshotInternalE*4base8Callback*
-   fun:*SaveScreenshotE*4base8Callback*
-}
 {
    bug_87232
    Memcheck:Uninitialized