compiler: conform to latest iteration of wasm types proposal (#4501)

compiler: align with current wasm types proposal

https://github.com/golang/go/issues/66984

- Remove int and uint as allowed types in params, results, pointers, or struct fields
- Only allow small integers in pointers, arrays, or struct fields
- enforce structs.HostLayout usage per wasm types proposal
https://github.com/golang/go/issues/66984
- require go1.23 for structs.HostLayout
- use an interface to check if GoVersion() exists
This permits TinyGo to compile with Go 1.21.
- use goenv.Compare instead of WantGoVersion
- testdata/wasmexport: use int32 instead of int
- compiler/testdata: add structs.HostLayout
- compiler/testdata: improve tests for structs.HostLayout

compiler/testdata/errors.go

@@ -1,6 +1,9 @@
 package main
 
-import "unsafe"
+import (
+	"structs"
+	"unsafe"
+)
 
 //go:wasmimport modulename empty
 func empty()
@@ -14,31 +17,37 @@ func implementation() {
 type Uint uint32
 
 type S struct {
+	_ structs.HostLayout
 	a [4]uint32
 	b uintptr
-	c int
 	d float32
 	e float64
 }
 
 //go:wasmimport modulename validparam
-func validparam(a int32, b uint64, c float64, d unsafe.Pointer, e Uint, f uintptr, g string, h *int32, i *S)
+func validparam(a int32, b uint64, c float64, d unsafe.Pointer, e Uint, f uintptr, g string, h *int32, i *S, j *struct{}, k *[8]uint8)
 
 // ERROR: //go:wasmimport modulename invalidparam: unsupported parameter type [4]uint32
 // ERROR: //go:wasmimport modulename invalidparam: unsupported parameter type []byte
 // ERROR: //go:wasmimport modulename invalidparam: unsupported parameter type struct{a int}
 // ERROR: //go:wasmimport modulename invalidparam: unsupported parameter type chan struct{}
 // ERROR: //go:wasmimport modulename invalidparam: unsupported parameter type func()
+// ERROR: //go:wasmimport modulename invalidparam: unsupported parameter type int
+// ERROR: //go:wasmimport modulename invalidparam: unsupported parameter type uint
+// ERROR: //go:wasmimport modulename invalidparam: unsupported parameter type [8]int
 //
 //go:wasmimport modulename invalidparam
-func invalidparam(a [4]uint32, b []byte, c struct{ a int }, d chan struct{}, e func())
+func invalidparam(a [4]uint32, b []byte, c struct{ a int }, d chan struct{}, e func(), f int, g uint, h [8]int)
+
+// ERROR: //go:wasmimport modulename invalidparam_no_hostlayout: unsupported parameter type *struct{int}
+// ERROR: //go:wasmimport modulename invalidparam_no_hostlayout: unsupported parameter type *struct{string}
+//
+//go:wasmimport modulename invalidparam_no_hostlayout
+func invalidparam_no_hostlayout(a *struct{ int }, b *struct{ string })
 
 //go:wasmimport modulename validreturn_int32
 func validreturn_int32() int32
 
-//go:wasmimport modulename validreturn_int
-func validreturn_int() int
-
 //go:wasmimport modulename validreturn_ptr_int32
 func validreturn_ptr_int32() *int32
 
@@ -48,6 +57,12 @@ func validreturn_ptr_string() *string
 //go:wasmimport modulename validreturn_ptr_struct
 func validreturn_ptr_struct() *S
 
+//go:wasmimport modulename validreturn_ptr_struct
+func validreturn_ptr_empty_struct() *struct{}
+
+//go:wasmimport modulename validreturn_ptr_array
+func validreturn_ptr_array() *[8]uint8
+
 //go:wasmimport modulename validreturn_unsafe_pointer
 func validreturn_unsafe_pointer() unsafe.Pointer
 
@@ -56,11 +71,26 @@ func validreturn_unsafe_pointer() unsafe.Pointer
 //go:wasmimport modulename manyreturns
 func manyreturns() (int32, int32)
 
+// ERROR: //go:wasmimport modulename invalidreturn_int: unsupported result type int
+//
+//go:wasmimport modulename invalidreturn_int
+func invalidreturn_int() int
+
+// ERROR: //go:wasmimport modulename invalidreturn_int: unsupported result type uint
+//
+//go:wasmimport modulename invalidreturn_int
+func invalidreturn_uint() uint
+
 // ERROR: //go:wasmimport modulename invalidreturn_func: unsupported result type func()
 //
 //go:wasmimport modulename invalidreturn_func
 func invalidreturn_func() func()
 
+// ERROR: //go:wasmimport modulename invalidreturn_pointer_array_int: unsupported result type *[8]int
+//
+//go:wasmimport modulename invalidreturn_pointer_array_int
+func invalidreturn_pointer_array_int() *[8]int
+
 // ERROR: //go:wasmimport modulename invalidreturn_slice_byte: unsupported result type []byte
 //
 //go:wasmimport modulename invalidreturn_slice_byte