Diagnose printf/scanf perf issues

[bushidocodes]

Xiaosu noticed that printf and scanf functions seem to cause a substantial slowdown of modules running under Sledge. This might be due to LTO, it might be Sledge-backing specific, or it might be here.

The scope of this task is to compare the overhead of scanf and printf under wasmception, wasi-sdk, and native to determine if this is an issue here or downstream.