[analyzer] StdLibraryFunctionsChecker: Add test for function with default parameter

Reviewers: Szelethus, baloghadamsoftware, gamesh411, steakhal, balazske

Subscribers: whisperity, xazax.hun, szepet, rnkovacs, a.sidorin, mikhail.ramalho, donat.nagy, dkrupp, Charusso, ASDenysPetrov, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D77411