fix: staticcheck and deadcode findings repo-wide, modernize counting loops

lint/corpus_test.go

@@ -5,8 +5,9 @@ package lint
 
 import (
 	"os"
+	"os/exec"
 	"path/filepath"
-	"runtime"
+	"strings"
 	"testing"
 
 	"sourcedock.dev/petrbalvin/gasm-devkit/arch"
@@ -24,7 +25,11 @@ import (
 // assembler accepts.  Advisory warnings are reported but not fatal, since they
 // are heuristics that may legitimately differ across Go versions.
 func TestGoRuntimeCorpus(t *testing.T) {
-	dir := filepath.Join(runtime.GOROOT(), "src", "runtime")
+	out, err := exec.Command("go", "env", "GOROOT").Output()
+	if err != nil {
+		t.Skipf("cannot locate GOROOT: %v", err)
+	}
+	dir := filepath.Join(strings.TrimSpace(string(out)), "src", "runtime")
 	var files []string
 	for _, suffix := range []string{"_amd64.s", "_arm64.s", "_riscv64.s", "_loong64.s"} {
 		matches, _ := filepath.Glob(filepath.Join(dir, "*"+suffix))