Remove clamping of kPlus with F16 configs

The most common use-case for F16 is to draw things that are explicitly
outside of [0,1]. We can't prevent out-of-range values in general, users
could just draw out-of-range content in src mode. We've decided that
it's best to avoid surprising behavior, and trust the user in these
situations.

This effectively reverts https://skia-review.googlesource.com/c/skia/+/48183

Bug: skia:
Change-Id: I71c2dd925c567e2862d96ab70c752f19245a69c4
Reviewed-on: https://skia-review.googlesource.com/140500
Reviewed-by: Mike Klein <mtklein@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
diff --git a/src/gpu/ops/GrTextureOp.cpp b/src/gpu/ops/GrTextureOp.cpp
index bced31d..108ee42 100644
--- a/src/gpu/ops/GrTextureOp.cpp
+++ b/src/gpu/ops/GrTextureOp.cpp
@@ -683,8 +683,7 @@
         return str;
     }
 
-    RequiresDstTexture finalize(const GrCaps& caps, const GrAppliedClip* clip,
-                                GrPixelConfigIsClamped dstIsClamped) override {
+    RequiresDstTexture finalize(const GrCaps& caps, const GrAppliedClip* clip) override {
         SkASSERT(!fFinalized);
         SkASSERT(1 == fProxyCnt);
         fFinalized = true;