[runtimes] Use int main(int, char**) consistently in tests
This is needed when running the tests in Freestanding mode, where main()
isn't treated specially. In Freestanding, main() doesn't get mangled as
extern "C", so whatever runtime we're using fails to find the entry point.
One way to solve this problem is to define a symbol alias from __Z4mainiPPc
to _main, however this requires all definitions of main() to have the same
mangling. Hence this commit.
GitOrigin-RevId: 504bc07d1afc7bad7b980a977141696ec8298e7e
47 files changed
