go_1_15: init at 1.15beta1 (#91463)

pkgs/development/compilers/go/skip-external-network-tests-1.15.patch

@@ -0,0 +1,13 @@
+diff --git a/src/net/dial_test.go b/src/net/dial_test.go
+index 01582489de..5b5faa5424 100644
+--- a/src/net/dial_test.go
++++ b/src/net/dial_test.go
+@@ -990,6 +990,8 @@ func TestDialerControl(t *testing.T) {
+ // except that it won't skip testing on non-mobile builders.
+ func mustHaveExternalNetwork(t *testing.T) {
+ 	t.Helper()
++	t.Skipf("Nix sandbox does not have networking")
++
+ 	mobile := runtime.GOOS == "android" || runtime.GOOS == "darwin" && runtime.GOARCH == "arm64"
+ 	if testenv.Builder() == "" || mobile {
+ 		testenv.MustHaveExternalNetwork(t)