lib: fix reference leak
confidence improvement accuracy (*) (**) (***)
process/next-tick-breadth-args.js n=10000000 -0.88 % ±2.88% ±3.84% ±5.01%
process/next-tick-breadth.js n=10000000 1.89 % ±6.65% ±8.84% ±11.51%
process/next-tick-depth-args.js n=7000000 -0.92 % ±2.44% ±3.25% ±4.23%
process/next-tick-depth.js n=7000000 ** -3.93 % ±2.92% ±3.88% ±5.06%
process/next-tick-exec-args.js n=4000000 0.97 % ±2.80% ±3.73% ±4.86%
process/next-tick-exec.js n=4000000 -0.05 % ±3.25% ±4.33% ±5.64%
process/next-tick-loop-args.js loop=1000 n=10000 *** 20.59 % ±2.88% ±3.83% ±4.98%
process/next-tick-loop-args.js loop=1000 n=20000 *** 12.65 % ±2.57% ±3.41% ±4.45%
process/next-tick-loop-args.js loop=1000 n=40000 *** 19.94 % ±2.52% ±3.36% ±4.39%
process/next-tick-loop.js loop=1000 n=10000 *** 8.85 % ±1.78% ±2.36% ±3.08%
process/next-tick-loop.js loop=1000 n=20000 *** 14.25 % ±1.53% ±2.04% ±2.67%
process/next-tick-loop.js loop=1000 n=40000 *** 21.86 % ±1.41% ±1.88% ±2.44%