Try/catch structure should be tree-shaken when try block is empty

[stephanedr]

• Rollup Version: 1.24.0
• Operating System (or Browser): Linux
• Node Version: 10.16.3

How Do We Reproduce?

With tryCatchDeoptimization=false.

try {
}
catch (e) {
    console.log();
}

Expected Behavior

Completely removed, as no errors can be thrown (should also be removed with tryCatchDeoptimization=true).

Note that if a finally block exists, it must be preserved (without the finally keyword).

Actual Behavior

try {
}
catch (e) {
    console.log();
}

[lukastaegert]

Good point, as it turns out, there is never a reason to look for side-effects in the catch block when determining if the try-statement as a whole has side-effects. Improved in #3166.