[gn build] Port 3b6bc87

Author: llvmgnsyncbot

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

@@ -699,9 +699,6 @@ if (current_toolchain == default_toolchain) {
       "__support/musl/xlocale.h",
       "__support/newlib/xlocale.h",
       "__support/openbsd/xlocale.h",
-      "__support/solaris/floatingpoint.h",
-      "__support/solaris/wchar.h",
-      "__support/solaris/xlocale.h",
       "__support/win32/locale_win32.h",
       "__support/xlocale/__nop_locale_mgmt.h",
       "__support/xlocale/__posix_l_fallback.h",