Function setReadFileCache

test/fixtures/snapshot/typescript.js:115900–115904

(key, fileName)

            return setReadFileCache(key, fileName);
        };
        var setReadFileCache = function (key, fileName) {
            var newValue = originalReadFile.call(host, fileName);
            readFileCache.set(key, newValue !== undefined ? newValue : false);
            return newValue;
        };
        host.readFile = function (fileName) {
            var key = toPath(fileName);
            var value = readFileCache.get(key);