time: use internal/itoa

In initLocal for GOOS=js, use internal/itoa introduced in CL 301549
instead of a local implementation.

Change-Id: If107d5cf0ce56f4d926507db2cbd6da422c6d15a
Reviewed-on: https://go-review.googlesource.com/c/go/+/425302
Auto-Submit: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Heschi Kreinick <heschi@google.com>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gopher Robot <gobot@golang.org>

src/time/zoneinfo_js.go

@@ -7,6 +7,7 @@
 package time
 
 import (
+	"internal/itoa"
 	"syscall/js"
 )
 
@@ -35,31 +36,10 @@ func initLocal() {
 	} else {
 		z.name += "+"
 	}
-	z.name += itoa(offset / 60)
+	z.name += itoa.Itoa(offset / 60)
 	min := offset % 60
 	if min != 0 {
-		z.name += ":" + itoa(min)
+		z.name += ":" + itoa.Itoa(min)
 	}
 	localLoc.zone = []zone{z}
 }
-
-// itoa is like strconv.Itoa but only works for values of i in range [0,99].
-// It panics if i is out of range.
-func itoa(i int) string {
-	if i < 10 {
-		return digits[i : i+1]
-	}
-	return smallsString[i*2 : i*2+2]
-}
-
-const smallsString = "00010203040506070809" +
-	"10111213141516171819" +
-	"20212223242526272829" +
-	"30313233343536373839" +
-	"40414243444546474849" +
-	"50515253545556575859" +
-	"60616263646566676869" +
-	"70717273747576777879" +
-	"80818283848586878889" +
-	"90919293949596979899"
-const digits = "0123456789"