Error patterns in UI tests do not allow normalized placeholders #90116
Description
For example, consider this test code:
rust/src/test/ui/symbol-names/const-generics-str-demangling.rs
Lines 38 to 42 in efd0483
After normalization of this to read
#[rustc_symbol_name] //~^ ERROR symbol-name(_RMs3_CsCRATE_HASH_1cINtB3_3StrKRef09f908af09fa688f09fa686f09f90ae20c2a720f09f90b6f09f9192e29895f09f94a520c2a720f09fa7a1f09f929bf09f929af09f9299f09f929c_E) //~| ERROR demangling(<c[HASH]::Str<"🐊🦈🦆🐮 § 🐶👒☕🔥 § 🧡💛💚💙💜">>) //~| ERROR demangling-alt(<c::Str<"🐊🦈🦆🐮 § 🐶👒☕🔥 § 🧡💛💚💙💜">>) impl Str<"🐊🦈🦆🐮 § 🐶👒☕🔥 § 🧡💛💚💙💜"> {} one must truncate the entire annotation, or the test will fail, even if the correct, normalized output is in the .stderr file.
See the discussion in #89836 (comment).