Cleanup references to concurrent_links in gn binary.

tools/gn/ninja_build_writer.cc

Index: tools/gn/ninja_build_writer.cc
diff --git a/tools/gn/ninja_build_writer.cc b/tools/gn/ninja_build_writer.cc
index a7f56f99722429d9d873f3bcdd538f202a1a7218..fba1ccb5a0b21a0ec323317b151b75b1e5084dcf 100644
--- a/tools/gn/ninja_build_writer.cc
+++ b/tools/gn/ninja_build_writer.cc
@@ -254,10 +254,6 @@ void NinjaBuildWriter::WriteNinjaRules() {
 }
 
 void NinjaBuildWriter::WriteAllPools() {
-  out_ << "pool link_pool\n"
-       << "  depth = " << default_toolchain_->concurrent_links() << std::endl
-       << std::endl;
-
   // Compute the pools referenced by all tools of all used toolchains.
   std::set<const Pool*> used_pools;
   for (const auto& pair : used_toolchains_) {