C++: Support implicit casts better in range analysis

[criemen]

This extends the C++ range analysis by supporting constructs like

int i;
long l;   
if (i < l - 2) {
  sink (i);
}

The bound derived in the if condition is on the value number of the implicitly-to-long converted i.
This PR recovers a bound on i itself.

Depends on #2745, *.expected test changes are missing due to missing tooling.

[rdmarsh2]

Looks good to me. I've added expected test output by pushing to your branch.

[rdmarsh2]

@jbj can we get @Cornelius-Riemenschneider a preview codeql version so he can run tests himself?

[dbartol]

LGTM