APPS: remove duplicate definition of `trace_data_stack`
Note: It seems like the C compiler doesn't care about the duplicate.
(The first definition is eight lines above.) The C++ compiler however
didn't like it when I reused the tracing code snippets elsewhere.
Reviewed-by: Matt Caswell <matt@openssl.org> Reviewed-by: Tom Cosgrove <tom.cosgrove@arm.com> Reviewed-by: Paul Dale <pauli@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/22117)