Support @ts-ignore for specific errors

TypeScript Version: 2.6.0-dev.20171011

Code

function countDown(n: number): void {
    switch (n) {
        // @ts-ignore
        case 1:
            console.log("1");
            // intentional fall through
        case 0:
            console.log("0");
    }
}

Expected behavior:

Ability to make ts-ignore apply to the --noFallthroughCasesInSwitch error but not to other errors.

Actual behavior:

case "1": would also compile.

Start with the TypeScript repro in the issue and inspect how the @ts-ignore comment is applied alongside --noFallthroughCasesInSwitch. Verify the behavior against both the intentional fall-through diagnostic and the case "1" type error; done means the former can be suppressed without suppressing the latter.