Interner arg to EarlyBinder does not affect auto traits

Conceptually `EarlyBinder` does not contain an `Interner` so it shouldn't tell Rust it does via `PhantomData`.
This is necessary for rust-analyzer as it stores `EarlyBinder`s in query results which require `Sync`, placing restrictions on our interner setup.

compiler/rustc_type_ir/src/binder.rs

@@ -357,7 +357,7 @@ impl<I: Interner> TypeVisitor<I> for ValidateBoundVars<I> {
 pub struct EarlyBinder<I: Interner, T> {
     value: T,
     #[derive_where(skip(Debug))]
-    _tcx: PhantomData<I>,
+    _tcx: PhantomData<fn() -> I>,
 }
 
 /// For early binders, you should first call `instantiate` before using any visitors.