misc/cgo/testplugin: skip TestIssue25756pie on darwin/arm64 builder

This test is known to be broken on the darwin/arm64 builder.
Skip it while it's being investigated so it doesn't mask other failures.

For #46239.
Updates #43228.

Change-Id: I8fe57a0636bba84c3100337146dcb96cc264e524
Reviewed-on: https://go-review.googlesource.com/c/go/+/321349
Trust: Dmitri Shuralyov <[email protected]>
Run-TryBot: Dmitri Shuralyov <[email protected]>
TryBot-Result: Go Bot <[email protected]>
Reviewed-by: Cherry Mui <[email protected]>

Author: dmitshur

misc/cgo/testplugin/plugin_test.go

@@ -265,6 +265,10 @@ func TestIssue25756(t *testing.T) {
 
 // Test with main using -buildmode=pie with plugin for issue #43228
 func TestIssue25756pie(t *testing.T) {
+	if os.Getenv("GO_BUILDER_NAME") == "darwin-arm64-11_0-toothrot" {
+		t.Skip("broken on darwin/arm64 builder in sharded mode; see issue 46239")
+	}
+
 	goCmd(t, "build", "-buildmode=plugin", "-o", "life.so", "./issue25756/plugin")
 	goCmd(t, "build", "-buildmode=pie", "-o", "issue25756pie.exe", "./issue25756/main.go")
 	run(t, "./issue25756pie.exe")