avoid some invalidations from untyped dict code in TOML print (#48908)

(cherry picked from commit 015301a)

Author: KristofferC

stdlib/TOML/src/print.jl

@@ -163,7 +163,8 @@ function print_table(f::MbyFunc, io::IO, a::AbstractDict,
         end
         if is_table(value)
             push!(ks, String(key))
-            header = isempty(value) || !all(is_tabular(v) for v in values(value))::Bool
+            _values = @invokelatest values(value)
+            header = isempty(value) || !all(is_tabular(v) for v in _values)::Bool
             if header
                 # print table
                 first_block || println(io)