Fix test on WASM target by making ambiguity pruning more agressive

Author: estebank

compiler/rustc_trait_selection/src/traits/error_reporting/type_err_ctxt_ext.rs

@@ -2103,7 +2103,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                 // It doesn't make sense to talk about applicable impls if there are more than a
                 // handful of them. If there are a lot of them, but only a few of them have no type
                 // params, we only show those, as they are more likely to be useful/intended.
-                if ambiguities.len() > 20 {
+                if ambiguities.len() > 5 {
                     let infcx = self.infcx;
                     if !ambiguities.iter().all(|option| match option {
                         DefId(did) => infcx.fresh_args_for_item(DUMMY_SP, *did).is_empty(),

tests/ui/traits/issue-77982.stderr

@@ -50,8 +50,6 @@ LL |     let ips: Vec<_> = (0..100_000).map(|_| u32::from(0u32.into())).collect(
            - impl From<char> for u32;
            - impl From<u16> for u32;
            - impl From<u8> for u32;
-           - impl<T> From<!> for T;
-           - impl<T> From<T> for T;
 help: try using a fully qualified path to specify the expected types
    |
 LL |     let ips: Vec<_> = (0..100_000).map(|_| u32::from(<u32 as Into<T>>::into(0u32))).collect();