wiki: update Memory Allocator Trace documentation

[kovan]

The GODEBUG=allocfreetrace=1 option was removed in Go 1.23.
Update the documentation to reflect current alternatives:

• Memory profiling with -memprofile and -memprofilerate=1
• GODEBUG=traceallocfree=1 with execution traces for advanced use

Also update the note about combining GODEBUG options to remove
the obsolete allocfreetrace reference.

Updates golang/go#75183

[gopherbot]

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