[gn build] Port 6d663cd

Author: llvmgnsyncbot

llvm/utils/gn/secondary/libcxx/include/BUILD.gn

@@ -1439,7 +1439,6 @@ if (current_toolchain == default_toolchain) {
       "__tuple/sfinae_helpers.h",
       "__tuple/tuple_element.h",
       "__tuple/tuple_like.h",
-      "__tuple/tuple_like_ext.h",
       "__tuple/tuple_like_no_subrange.h",
       "__tuple/tuple_size.h",
       "__tuple/tuple_types.h",