Add valgrind suppression for leak in libGLX_nvidia when caching program binaries

Change-Id: Id6d32811c59b5d37579a1c1bf0f42e85d951d45f
Reviewed-on: https://skia-review.googlesource.com/141821
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>

tools/valgrind.supp

@@ -100,6 +100,12 @@
    fun:sendmsg
    obj:*/libGLX_nvidia.so*
 }
+{
+   nv_driver_bug_5
+   Memcheck:Leak
+   fun:malloc
+   obj:*/libGLX_nvidia.so*
+}
 {
     #Fixed by FontConfig 2.9.0
     #http://cgit.freedesktop.org/fontconfig/commit/?id=1c475d5c8cb265ac939d6b9e097666e300162511