[clang-tidy] modernize-avoid-c-arrays: avoid main function (PR40604)

Summary:
The check should ignore the main function, the program entry point.
It is not possible to use `std::array<>` for the `argv`.
The alternative is to use `char** argv`.

Fixes [[ https://bugs.llvm.org/show_bug.cgi?id=40604 | PR40604 ]]

Reviewers: JonasToth, aaron.ballman

Reviewed By: aaron.ballman

Subscribers: xazax.hun, hans, cfe-commits

Tags: #clang-tools-extra, #clang

Differential Revision: https://reviews.llvm.org/D57787

llvm-svn: 353327