Refactor malloc+memset to use calloc #2497
When a zeroed out allocation is required, most callsites in the code use
Also remove to calls to
When a zeroed out allocation is required, use calloc() rather than malloc() followed by an explicit memset(). The result will be the same, but using calloc() everywhere increases consistency in the codebase and avoids the risk of subtle bugs when code is injected between malloc and memset by accident.