[DAM analyzer] support exceptional control flow

[sbomer]

Creating this issue for tracking purposes.

Currently the analyzer assumes control flow is linear inside of a basic block, and doesn't account for the implicit control flow from anywhere inside a try block to the beginning of a catch/finally block, or from anywhere inside a catch to the beginning of a finally block. The analyzer also throws an when it sees a throw operation (which isn't supported yet).

[sbomer]

#2481 mostly completes this, but a little more work is needed to ensure we produce warnings for exception filters.