files.PutFile: panic when file with zero size

[wuxu92]

fileInfo.Size() can be 0 so Line 25 will cause 0/0 which is

The result of a floating-point or complex division by zero is not specified beyond the IEEE-754 standard; whether a run-time panic occurs is implementation-specific.
Ref: https://go.dev/ref/spec#Floating_point_operators

The division did not cause panic but the value of chucks is Inf but panic with "makechan: size out of range" in line 35.

giovanni/storage/2020-08-04/file/files/range_put_file.go

Lines 20 to 35 in 5e72bd2

	fileSize := fileInfo.Size()
	chunkSize := 4 * 1024 * 1024 // 4MB
	if chunkSize > int(fileSize) {
	chunkSize = int(fileSize)
	}
	chunks := int(math.Ceil(float64(fileSize) / float64(chunkSize*1.0)))
	workerCount := parallelism
	if workerCount > chunks {
	workerCount = chunks
	}
	var waitGroup sync.WaitGroup
	waitGroup.Add(workerCount)
	jobs := make(chan int, workerCount)

Related Issue: hashicorp/terraform-provider-azurerm#24171