[4fGradient] Relax interval checks for SkGradientShaderBase also

Similar to https://skia-review.googlesource.com/8270, treat intervals
as closed at both extremities in the 4f gradient fallback impl also.

BUG=skia:6212

Change-Id: I7f164868202ae6a0f76cbcdbcbf8e62db12a1bd4
Reviewed-on: https://skia-review.googlesource.com/8277
Commit-Queue: Florin Malita <[email protected]>
Reviewed-by: Mike Reed <[email protected]>
diff --git a/fuzz/FuzzGradients.cpp b/fuzz/FuzzGradients.cpp
index 8539f5a..88f3429 100644
--- a/fuzz/FuzzGradients.cpp
+++ b/fuzz/FuzzGradients.cpp
@@ -75,7 +75,7 @@
     }
 
     SkDebugf("--- fuzzLinearGradient ---\n");
-    SkDebugf("  pts:\t\t[ (%f %f) (%f %f) ]\n",
+    SkDebugf("  pts:\t\t[ (%.9g %.9g) (%.9g %.9g) ]\n",
              pts[0].x(), pts[0].y(), pts[1].x(), pts[1].y());
     SkDebugf("  colors:\t[ ");
     for (auto color : colors) {