The #compiler struct attribute + #compiler-suffixed bodyless methods were
fully superseded by abi(.compiler) (P5.5) — no sx code uses them.
Remove the hash_compiler token (token/lexer/lsp), the is_compiler_struct /
struct_default_compiler parser machinery + the two compiler_expr body-
synthesis branches, the compiler_expr AST variant, and every
.builtin_expr/.compiler_expr switch arm + == .compiler_expr check across
sema/resolver/semantic_diagnostics/generic/decl/call/calls (kept .builtin_expr).
abi(.compiler) is untouched. Delete the obsolete calls.test.zig dispatch test.
500/500 unit + 706/0 corpus.
64eb01918a