[libc++] Remove unused _LIBCPP_HAS_NO_STD_MODULES macro from __config_site (llvm#148902)

Since 1d6b613, that macro isn't used anywhere anymore.

Author: ldionne

libcxx/include/__config_site.in

@@ -30,7 +30,6 @@
 #cmakedefine01 _LIBCPP_HAS_LOCALIZATION
 #cmakedefine01 _LIBCPP_HAS_UNICODE
 #cmakedefine01 _LIBCPP_HAS_WIDE_CHARACTERS
-#cmakedefine _LIBCPP_HAS_NO_STD_MODULES
 #cmakedefine01 _LIBCPP_HAS_TIME_ZONE_DATABASE
 #cmakedefine01 _LIBCPP_INSTRUMENTED_WITH_ASAN
 

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

@@ -35,7 +35,6 @@ if (current_toolchain == default_toolchain) {
       "_LIBCPP_HAS_LOCALIZATION=1",
       "_LIBCPP_HAS_UNICODE=1",
       "_LIBCPP_HAS_WIDE_CHARACTERS=1",
-      "_LIBCPP_HAS_NO_STD_MODULES=",
       "_LIBCPP_HAS_TERMINAL=1",
       "_LIBCPP_INSTRUMENTED_WITH_ASAN=",
       "_LIBCPP_ABI_DEFINES=",