[clang-tidy] detect unnecessary try-catch blocks

[firewave]

void cb() noexcept;

void f()
{
    try {
        cb();
    } catch(...) {}
}

In this case the try-catch is unnecessary as nothing in the scope is throwing.

[llvmbot]

@llvm/issue-subscribers-clang-tidy

Author: Oliver Stöneberg (firewave)

```cpp void cb() noexcept;

void f()
{
try {
cb();
} catch(...) {}
}

In this case the try-catch is unnecessary as nothing in the scope is throwing.
</details>

[firewave]

The initial implementation should only check if any exception can be thrown and report completely unnecessary try-catch blocks.

At a later date that could be improved to also check if the handled exception types are possible for visible functions. I reckon anything else needs to be implemented in the static analyzer.