ci: support blst portable build

[yoomee1313]

Proposed changes

• This PR added CGO_CFLAGS="-O2 -g -D__BLST_PORTABLE__" when building klaytn binary to support blst portable build

Types of changes

• Bugfix
• New feature or enhancement
• Others

Checklist

• I have read the CONTRIBUTING GUIDELINES doc
• I have signed the CLA
• Lint and unit tests pass locally with my changes ($ make test)
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)
• Any dependent changes have been merged and published in downstream modules

Related issues

#2076

Further comments

• Performance Test. @blukat29
  • environment is m6i.xlarge (Intel(R) Xeon(R) Platinum 8375C CPU @ 2.90GHz)
  • cpuid: ADX instructions = true, SHA instructions = true (optimized instruction works)
  • test fn: blst go binding (https://github.com/supranational/blst/tree/master/bindings/go) BenchmarkCoreSignMinPk
  • test result
    • blst library v0.3.10 (without runtime detection): Default 420,000 ns/op, Portable 530,000 ns/op
    • blst library v0.3.11 (with runtime detection): Default 420,000 ns/op, Portable 420,000 ns/op
  • conclusion
    • Runtime detection at v0.3.11 works. Portable binary automatically optimizes depending on the environment.
• Compatibility Test
  • Check the docker image generated in x86_64 works at m1. → works well
  • Check the intel mac binary works at m1. → works well
  • Check if CGO_CFLAGS works. -> settings are correct
• How to check if a binary is porable

# Portable. Built with CGO_CFLAGS
$ strings build/bin/ken | grep CGO_CFLAGS
build	CGO_CFLAGS="-O2 -g -D__BLST_PORTABLE__"
build	CGO_CFLAGS="-O2 -g -D__BLST_PORTABLE__"

# Not portable. Built without CGO_CFLAGS
$ strings build/bin/ken | grep CGO_CFLAGS       
CGO_CFLAGS=""
CGO_CFLAGS=""

[blukat29]

@yoomee1313 The -g flag adds debug symbols to the binary. Please check if binary size increases.

[yoomee1313]

@blukat29 The binary size is same. 53M. Referenced from geth code.
https://github.com/ethereum/go-ethereum/blob/c66ca8bf7a8c63ae54e44f4566e206cd1a4fa204/internal/build/gotool.go#L58.