testing/gomp: update go.{mod/sum} to build loongarch64

Signed-off-by: yzewei <yangzewei@loongson.cn>

testing/gomp/APKBUILD

@@ -11,6 +11,12 @@ makedepends="go"
 source="$pkgname-$pkgver.tar.gz::https://github.com/aditya-K2/gomp/archive/refs/tags/v$pkgver.tar.gz"
 options="!check" # no tests suite
 
+prepare() {
+	default_prepare
+	go get -u golang.org/x/sys@v0.21.0
+	go mod tidy
+}
+
 build() {
 	go generate
 	go build