Add fuzzer option for Blur w/o occluder

I hypothesize that some backends look at the occluder and may have
accidentally (on purpose) been avoiding the linked bug.

Bug: skia:7956
Change-Id: If8d1de099f778b2faaa2c5ed4c562047b0dd14e7
Reviewed-on: https://skia-review.googlesource.com/131922
Commit-Queue: Kevin Lubick <kjlubick@google.com>
Reviewed-by: Hal Canary <halcanary@google.com>
diff --git a/fuzz/FuzzCanvas.cpp b/fuzz/FuzzCanvas.cpp
index 8e84e88..5c92fd1 100644
--- a/fuzz/FuzzCanvas.cpp
+++ b/fuzz/FuzzCanvas.cpp
@@ -498,13 +498,17 @@
             SkScalar sigma;
             fuzz->next(&sigma);
             SkRect occluder{0.0f, 0.0f, 0.0f, 0.0f};
-            if (make_fuzz_t<bool>(fuzz)) {
+            bool useOccluder;
+            fuzz->next(&useOccluder);
+            if (useOccluder) {
                 fuzz->next(&occluder);
             }
-            uint32_t flags;
-            fuzz->nextRange(&flags, 0, 1);
-            bool respectCTM = flags != 0;
-            return SkMaskFilter::MakeBlur(blurStyle, sigma, occluder, respectCTM);
+            bool respectCTM;
+            fuzz->next(&respectCTM);
+            if (useOccluder) {
+                return SkMaskFilter::MakeBlur(blurStyle, sigma, occluder, respectCTM);
+            }
+            return SkMaskFilter::MakeBlur(blurStyle, sigma, respectCTM);
         }
         default:
             SkASSERT(false);