[vm, reload] Preserve libraries' ffi_native_resolver.

TEST=reload bots
Bug: #53808
Change-Id: I2e86c9425867278a6986b5fac6ead9e587c3aa9d
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/331203
Reviewed-by: Ben Konyi <bkonyi@google.com>
Commit-Queue: Ryan Macnak <rmacnak@google.com>

runtime/vm/isolate_reload.cc

@@ -1666,6 +1666,7 @@ void ProgramReloadContext::CommitBeforeInstanceMorphing() {
         new_lib.set_native_entry_resolver(lib.native_entry_resolver());
         new_lib.set_native_entry_symbol_resolver(
             lib.native_entry_symbol_resolver());
+        new_lib.set_ffi_native_resolver(lib.ffi_native_resolver());
       }
     }