Rollup merge of rust-lang#99643 - daxpedda:sign-ext-wasm, r=oli-obk

Add `sign-ext` target feature to the WASM target

Some target features are still missing from that list.
See rust-lang#97808 for basically the same PR by `@alexcrichton.`

Related issue: rust-lang#96472.
PR introducing this issue: rust-lang#87402.

compiler/rustc_codegen_ssa/src/target_features.rs

@@ -249,6 +249,7 @@ const WASM_ALLOWED_FEATURES: &[(&str, Option<Symbol>)] = &[
     ("bulk-memory", Some(sym::wasm_target_feature)),
     ("mutable-globals", Some(sym::wasm_target_feature)),
     ("reference-types", Some(sym::wasm_target_feature)),
+    ("sign-ext", Some(sym::wasm_target_feature)),
 ];
 
 const BPF_ALLOWED_FEATURES: &[(&str, Option<Symbol>)] = &[("alu32", Some(sym::bpf_target_feature))];