tests/attrtest: move decl to non-test file

Solves the asmdecl error:

  [amd64] AttrTest: function AttrTest missing Go declaration

Updates #24

tests/textflag/attrtest.go

@@ -0,0 +1,6 @@
+// Package textflag tests that avo attribute constants agree with textflag.h.
+package textflag
+
+//go:generate go run make_attrtest.go -output zattrtest.s -seed 42 -num 256
+
+func attrtest() bool

tests/textflag/attrtest_test.go

@@ -2,12 +2,8 @@ package textflag
 
 import "testing"
 
-//go:generate go run make_attrtest.go -output zattrtest.s -seed 42 -num 256
-
-func AttrTest() bool
-
 func TestAttributes(t *testing.T) {
-	if !AttrTest() {
+	if !attrtest() {
 		t.Fail()
 	}
 }

tests/textflag/doc.go

@@ -1,2 +0,0 @@
-// Package textflag tests that avo attribute constants agree with textflag.h.
-package textflag

tests/textflag/make_attrtest.go

@@ -44,7 +44,7 @@ func PrintAttributesTest(w io.Writer, as []attr.Attribute) {
 	_, self, _, _ := runtime.Caller(0)
 	fmt.Fprintf(w, "// Code generated by %s. DO NOT EDIT.\n\n", filepath.Base(self))
 	fmt.Fprintf(w, "#include \"textflag.h\"\n\n")
-	fmt.Fprintf(w, "TEXT ·AttrTest(SB), $0-1\n")
+	fmt.Fprintf(w, "TEXT ·attrtest(SB), $0-1\n")
 	fmt.Fprintf(w, "\tMOVB $0, ret+0(FP)\n")
 
 	for i, a := range as {

tests/textflag/zattrtest.s

@@ -2,7 +2,7 @@
 
 #include "textflag.h"
 
-TEXT ·AttrTest(SB), $0-1
+TEXT ·attrtest(SB), $0-1
 	MOVB $0, ret+0(FP)
 	MOVW $(1), R8
 	MOVW $(NOPROF), R9