Remove all clamping to "valid" premultiplied colors

Previously, we were abundantly cautious about producing premultiplied
colors with RGB > A, when the color-type was normalized fixed-point.

I'm not seeing any evidence that code cares about that. If it does, I
suggest we fix the issue at the API border, or via dedicated pass. In
the common case, this makes Skia less opinionated, which (in general)
makes it more versatile.

Change-Id: Iae524ff61f6c81073c34d0f2dced973c229cdfb7
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/452558
Reviewed-by: Brian Salomon <bsalomon@google.com>
Reviewed-by: Herb Derby <herb@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
diff --git a/tests/SkDSLRuntimeEffectTest.cpp b/tests/SkDSLRuntimeEffectTest.cpp
index f9a197e..8b7f0e9 100644
--- a/tests/SkDSLRuntimeEffectTest.cpp
+++ b/tests/SkDSLRuntimeEffectTest.cpp
@@ -142,7 +142,7 @@
         effect.uniform(SkString(gColor.name()).c_str()) = float4{ 0.0f, 0.25f, 0.75f, 1.0f };
         effect.test(0xFFBF4000);
         effect.uniform(SkString(gColor.name()).c_str()) = float4{ 1.0f, 0.0f, 0.0f, 0.498f };
-        effect.test(0x7F00007F);  // Tests that we clamp to valid premul
+        effect.test(0x7F0000FF);  // Tests that we don't clamp to valid premul
     }
 
     // Same, with integer uniforms
@@ -158,7 +158,7 @@
         effect.uniform(SkString(gColor.name()).c_str()) = int4{ 0x00, 0x40, 0xBF, 0xFF };
         effect.test(0xFFBF4000);
         effect.uniform(SkString(gColor.name()).c_str()) = int4{ 0xFF, 0x00, 0x00, 0x7F };
-        effect.test(0x7F00007F);  // Tests that we clamp to valid premul
+        effect.test(0x7F0000FF);  // Tests that we don't clamp to valid premul
     }
 
     // Test sk_FragCoord (device coords). Rotate the canvas to be sure we're seeing device coords.