Miscounting func size in internal/sizebench

[egonelbre]

Currently there seems to be some padding included in the go tool nm -size output. objdump ends up printing this:

  :-1                   0x1093ae5               cc                      INT $0x3
  :-1                   0x1093ae6               cc                      INT $0x3
  :-1                   0x1093ae7               cc                      INT $0x3
  :-1                   0x1093ae8               cc                      INT $0x3
  :-1                   0x1093ae9               cc                      INT $0x3
  :-1                   0x1093aea               cc                      INT $0x3
  :-1                   0x1093aeb               cc                      INT $0x3
  :-1                   0x1093aec               cc                      INT $0x3
  :-1                   0x1093aed               cc                      INT $0x3
  :-1                   0x1093aee               cc                      INT $0x3
  :-1                   0x1093aef               cc                      INT $0x3
  :-1                   0x1093af0               cc                      INT $0x3
  :-1                   0x1093af1               cc                      INT $0x3
  :-1                   0x1093af2               cc                      INT $0x3
  :-1                   0x1093af3               cc                      INT $0x3
  :-1                   0x1093af4               cc                      INT $0x3
  :-1                   0x1093af5               cc                      INT $0x3
  :-1                   0x1093af6               cc                      INT $0x3
  :-1                   0x1093af7               cc                      INT $0x3
  :-1                   0x1093af8               cc                      INT $0x3
  :-1                   0x1093af9               cc                      INT $0x3
  :-1                   0x1093afa               cc                      INT $0x3
  :-1                   0x1093afb               cc                      INT $0x3
  :-1                   0x1093afc               cc                      INT $0x3
  :-1                   0x1093afd               cc                      INT $0x3
  :-1                   0x1093afe               cc                      INT $0x3
  :-1                   0x1093aff               cc                      INT $0x3

Write better func size measurement.