Optimize the pipeline by removing @auto_init_metadata annotation

[Yi-Tseng]

As per suggestion from Vladimir/Barefoot. We should not use @auto_init_metadata and set metadata explicitly.

Ref: https://community.intel.com/t5/Intel-Connectivity-Research/Compiler-stuck-when-compiling-P4-code/m-p/1258686/highlight/false#M2157