Describe your changes

My PR adds very straightforward tests to trigger complilation errors with diagnostic notes. I didn't cover all library function and all error branches. But hopefully these basic tests could be helpul for future testing of library functions.

Covered functions:

• reflect_invoke
• identifier_of
• template_of
• type_of
• parent_of
• operator_of
• value_of
• object_of
• extract
• can_substitute
• substitute

I tried to follow test files pattern so for related *.pass.cpp I added *.verify.cpp files with validation of compilation error diagnostic.

Additional context

Found at least 1 bug:
Code below doesn't produce an error and prints A. But in source code of function identifier_of I see that we should error on this condition with note names of constructors are not identifiers

Maybe I am missing something...

#include <experimental/meta>
#include <iostream>


struct A {
  constexpr A() {}
};

int main() {
    std::cout << std::meta::identifier_of(^^A::A);
    // expected: names of constructors are not identifiers
    return 0;
}