Incomplete instrumentation for method as class property

[nil-s-s]

Following class is incompletely covered, the code in propertyFunction is not covered, only the assignment:

class Testing {
    method() {
        return 'Hello, World! ' + this.propertyFunction();
    }

    propertyFunction = () => {
        return 'Instance';
    };
}

export { Testing };

This is the resulting report. Line 7 is not covered by instrumentation.

[kwonoj]

Similar to #247 (comment), I'm open to accept a PR.