Sego adds many extra cmdline flags to the packages that imports sego

[bigwhite]

hi, huichen
I unconsciously found the sego package would add many extra cmdline flags to the packages that imports sego. And these flags are from testing package.
The code example is like below:

//test.go
package main

import (
    "flag"
    "fmt"

    _ "github.com/huichen/sego"
)

var logfile string

func usage() {
    flag.PrintDefaults()
}

func init() {
    flag.StringVar(&logfile, "logfile", "./log/log.txt", "the log file path")
}
func main() {
    flag.Usage = usage
    flag.Parse()
    fmt.Println("app run ok")
}

run the app：

$go run test.go -help
  -logfile string
        the log file path (default "./log/log.txt")
  -test.bench string
        regular expression per path component to select benchmarks to run
  -test.benchmem
        print memory allocations for benchmarks
  -test.benchtime duration
        approximate run time for each benchmark (default 1s)
  -test.blockprofile string
        write a goroutine blocking profile to the named file after execution
  -test.blockprofilerate int
        if >= 0, calls runtime.SetBlockProfileRate() (default 1)
  -test.count n
        run tests and benchmarks n times (default 1)
  -test.coverprofile string
        write a coverage profile to the named file after execution
  -test.cpu string
        comma-separated list of number of CPUs to use for each test
  -test.cpuprofile string
        write a cpu profile to the named file during execution
  -test.memprofile string
        write a memory profile to the named file after execution
  -test.memprofilerate int
        if >=0, sets runtime.MemProfileRate
  -test.outputdir string
        directory in which to write profiles
  -test.parallel int
        maximum test parallelism (default 4)
  -test.run string
        regular expression to select tests and examples to run
  -test.short
        run smaller test suite to save time
  -test.timeout duration
        if positive, sets an aggregate time limit for all tests
  -test.trace string
        write an execution trace to the named file after execution
  -test.v

verbose: print additional output
exit status 2

I did some debugging and I found the reason for this is that test_utils.go in sego imports "testing". I think it is not a good experience for sego users.

A simple approach to fix it is that renaming test_utils.go to utils_test.go. After this, the compiler will ignore the content in this file when building non-test package.