static_assert() condition cannot result in unsafe buffer access

[pkasting]

In issue 92191 we discovered -Wunsafe-buffer-usage warns on conditions inside static_asserts despite the fact that they are not executed at runtime and thus cannot result in an unsafe buffer access. The following snippet demonstrates this.

void foo() {
  int j[1] = {0};
  static_assert(j + 1 != nullptr);  // Erroneously warns
}

Live repro: https://godbolt.org/z/Y5onbr88W
@haoNoQ @jkorous-apple