transform: remove switched func lowering

The switched func lowering was mainly necessary for coroutines.
With coroutines removed, this is no longer necessary.

compiler/compiler_test.go

@@ -55,7 +55,7 @@ func TestCompiler(t *testing.T) {
 		{"string.go", "", ""},
 		{"float.go", "", ""},
 		{"interface.go", "", ""},
-		{"func.go", "", "none"},
+		{"func.go", "", ""},
 		{"pragma.go", "", ""},
 		{"goroutine.go", "wasm", "asyncify"},
 		{"goroutine.go", "cortex-m-qemu", "tasks"},
@@ -105,7 +105,6 @@ func TestCompiler(t *testing.T) {
 				CodeModel:          config.CodeModel(),
 				RelocationModel:    config.RelocationModel(),
 				Scheduler:          config.Scheduler(),
-				FuncImplementation: config.FuncImplementation(),
 				AutomaticStackSize: config.AutomaticStackSize(),
 				DefaultStackSize:   config.Target.DefaultStackSize,
 				NeedsStackObjects:  config.NeedsStackObjects(),