Renames Settings ⚠️ (fixes #976) (#1321)

This is a breaking API change: the following settings have been renamed:

- jump_tables_enabled -> enable_jump_tables
- colocated_libcalls -> use_colocated_libcalls
- probestack_enabled -> enable_probestack
- allones_funcaddrs -> emit_all_ones_funcaddrs

cranelift/codegen/src/legalizer/mod.rs

@@ -191,7 +191,7 @@ pub fn legalize_function(func: &mut ir::Function, cfg: &mut ControlFlowGraph, is
     }
 
     // Now that we've lowered all br_tables, we don't need the jump tables anymore.
-    if !isa.flags().jump_tables_enabled() {
+    if !isa.flags().enable_jump_tables() {
         pos.func.jump_tables.clear();
     }
 }
@@ -276,7 +276,7 @@ fn expand_br_table(
     cfg: &mut ControlFlowGraph,
     isa: &dyn TargetIsa,
 ) {
-    if isa.flags().jump_tables_enabled() {
+    if isa.flags().enable_jump_tables() {
         expand_br_table_jt(inst, func, cfg, isa);
     } else {
         expand_br_table_conds(inst, func, cfg, isa);