fix: ARG/ENV used in script does not invalidate build cache (#1688)

[madawei2699]

Fixes #1688

Description

In this PR, I added a change:

1. build compositeKey with args or envs.

This can ensure consistency with docker's behavior which is:

• docker use args/envs and cmd to build compositeKey

func TestPrependEnvOnCmd(t *testing.T) {
	buildArgs := NewBuildArgs(nil)
	buildArgs.AddArg("NO_PROXY", nil)

	args := []string{"sorted=nope", "args=not", "http_proxy=foo", "NO_PROXY=YA"}
	cmd := []string{"foo", "bar"}
	cmdWithEnv := prependEnvOnCmd(buildArgs, args, cmd)
	expected := strslice.StrSlice([]string{
		"|3", "NO_PROXY=YA", "args=not", "sorted=nope", "foo", "bar"})
	assert.Check(t, is.DeepEqual(expected, cmdWithEnv))
}

and also this can solved not expect cached command which run scripts that used args/envs.

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[madawei2699]

@googlebot I signed it!

[imjasonh]

Please rebase to get recent CI runs.

[madawei2699]

@imjasonh done