internal/lsp: fix variable reuse bug in code actions

Taking the address of the variables defined by range in a for loop is not
safe since they are reused. Get the address from the original slice.

Change-Id: If7fbf3fdbfeeaf329f36e416642582002895bbce
Reviewed-on: https://go-review.googlesource.com/c/tools/+/330649
Trust: Suzy Mueller <suzmue@golang.org>
Run-TryBot: Suzy Mueller <suzmue@golang.org>
gopls-CI: kokoro <noreply+kokoro@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Rebecca Stambler <rstambler@golang.org>

internal/lsp/code_action.go

@@ -312,11 +312,11 @@ func extractionFixes(ctx context.Context, snapshot source.Snapshot, pkg source.P
 		commands = append(commands, cmd)
 	}
 	var actions []protocol.CodeAction
-	for _, cmd := range commands {
+	for i := range commands {
 		actions = append(actions, protocol.CodeAction{
-			Title:   cmd.Title,
+			Title:   commands[i].Title,
 			Kind:    protocol.RefactorExtract,
-			Command: &cmd,
+			Command: &commands[i],
 		})
 	}
 	return actions, nil