resolve: Do not put nonexistent crate meta into prelude

compiler/rustc_resolve/src/lib.rs

@@ -1240,9 +1240,6 @@ impl<'a> Resolver<'a> {
             extern_prelude.insert(Ident::with_dummy_span(sym::core), Default::default());
             if !session.contains_name(&krate.attrs, sym::no_std) {
                 extern_prelude.insert(Ident::with_dummy_span(sym::std), Default::default());
-                if session.rust_2018() {
-                    extern_prelude.insert(Ident::with_dummy_span(sym::meta), Default::default());
-                }
             }
         }
 

src/test/ui/rfc-2126-extern-absolute-paths/meta.rs

@@ -1,7 +0,0 @@
-// edition:2018
-
-// Tests that `meta` is allowed, even if the crate doesn't exist
-// yet (i.e., it causes a different error than `not-allowed.rs`).
-use meta; //~ ERROR can't find crate for `meta`
-
-fn main() {}

src/test/ui/rfc-2126-extern-absolute-paths/meta.stderr

@@ -1,9 +0,0 @@
-error[E0463]: can't find crate for `meta`
-  --> $DIR/meta.rs:5:5
-   |
-LL | use meta;
-   |     ^^^^ can't find crate
-
-error: aborting due to previous error
-
-For more information about this error, try `rustc --explain E0463`.