Fix bug in Blend that did not use options.

For one of the many variants of Blend, a cut&paste error made
that the options were not passed.

This was not caught because no test exercised this.

I've added the test (in a related CL) and fixed the bug.

Bug: 178718752
Test: Ran the RS Java tests
Change-Id: Ide2fef96137ffd89e4431cf15be5df398036d909

rs/java/android/renderscript/ScriptIntrinsicBlend.java

@@ -99,7 +99,7 @@ public class ScriptIntrinsicBlend extends ScriptIntrinsic {
      * @param opt LaunchOptions for clipping
      */
     public void forEachSrc(Allocation ain, Allocation aout, Script.LaunchOptions opt) {
-        blend(1, ain, aout, null);
+        blend(1, ain, aout, opt);
     }
 
     /**
@@ -636,4 +636,3 @@ public class ScriptIntrinsicBlend extends ScriptIntrinsic {
     }
 */
 }
-