Expand suppressions for v8 external strings being leaked, due to no GC.

tools/heapcheck/suppressions.txt

Index: tools/heapcheck/suppressions.txt
diff --git a/tools/heapcheck/suppressions.txt b/tools/heapcheck/suppressions.txt
index 282a1d6165fd3cc4b031e35a667c9aabb969464a..34995e8a99f8ea069d9b8eba01c504534f467d1c 100644
--- a/tools/heapcheck/suppressions.txt
+++ b/tools/heapcheck/suppressions.txt
@@ -679,6 +679,20 @@
    fun:net::::LoadScriptData
 }
 {
+   bug_67378_c
+   Heapcheck:Leak
+   fun:net::::ASCIILiteralToV8String
+   fun:net::ProxyResolverV8::Context::InitV8
+   fun:net::ProxyResolverV8::SetPacScript
+}
+{
+   bug_67378_d
+   Heapcheck:Leak
+   fun:net::::ScriptDataToV8String
+   fun:net::ProxyResolverV8::Context::InitV8
+   fun:net::ProxyResolverV8::SetPacScript
+}
+{
    bug_68304
    Heapcheck:Leak
    ...