LLVM emits an unwind table entry for a function that may unwind or that
has the uwtable attribute. Functions it infers nounwind, such as the
number-key Map probe sc_map_entry_f64_hashed, got none, so profilers and
debuggers could not unwind past them. The function attribute groups now
carry uwtable on native targets; wasm32-wasi modules are unchanged.
Chris Tate
e1eead091f