bug fix in hsl GM reference impls
bug fix in hsl GM reference impls

As written the "constants" in clip() and channel() change as we update
each channel... duh.  Thankfully this ought to make most GMs look good.

Change-Id: I904e20e8e5114c827233dd1a93c0c59f7e7790fa
Reviewed-on: https://skia-review.googlesource.com/15680
Reviewed-by: Mike Klein <14574f09dfa9b4e14759b88c3426a495a0e627b0@chromium.org>
Commit-Queue: Mike Klein <14574f09dfa9b4e14759b88c3426a495a0e627b0@chromium.org>

rubenvb/skia,aosp-mirror/platform_external_skia,rubenvb/skia,google/skia,HalCanary/skia-hc,google/skia,google/skia,rubenvb/skia,HalCanary/skia-hc,aosp-mirror/platform_external_skia,google/skia,aosp-mirror/platform_external_skia,HalCanary/skia-hc,HalCanary/skia-hc,HalCanary/skia-hc,Hikari-no-Tenshi/android_external_skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,rubenvb/skia,rubenvb/skia,aosp-mirror/platform_external_skia,Hikari-no-Tenshi/android_external_skia,aosp-mirror/platform_external_skia,Hikari-no-Tenshi/android_external_skia,Hikari-no-Tenshi/android_external_skia,aosp-mirror/platform_external_skia,rubenvb/skia,Hikari-no-Tenshi/android_external_skia,google/skia,Hikari-no-Tenshi/android_external_skia,aosp-mirror/platform_external_skia,google/skia,google/skia,rubenvb/skia,HalCanary/skia-hc,rubenvb/skia,rubenvb/skia,google/skia,aosp-mirror/platform_external_skia,google/skia,HalCanary/skia-hc,Hikari-no-Tenshi/android_external_skia,HalCanary/skia-hc,HalCanary/skia-hc,Hikari-no-Tenshi/android_external_skia,HalCanary/skia-hc,rubenvb/skia,google/skia