[libc++] Remove __concepts/core_convertible_to.h in BUILD.gn

Signed-off-by: yronglin <[email protected]>

Author: yronglin

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

@@ -382,7 +382,6 @@ if (current_toolchain == default_toolchain) {
       "__concepts/constructible.h",
       "__concepts/convertible_to.h",
       "__concepts/copyable.h",
-      "__concepts/core_convertible_to.h",
       "__concepts/derived_from.h",
       "__concepts/destructible.h",
       "__concepts/different_from.h",