This iOS crash makes little sense to me.  Add some debugging.

We called new float[...].  The pointer returned should be aligned for float writes.

See https://uberchromegw.corp.google.com/i/client.skia/builders/Test-iOS-Clang-iPad4-GPU-SGX554-Arm7-Release

BUG=skia:

Review URL: https://codereview.chromium.org/1270403006
diff --git a/src/gpu/GrTestUtils.cpp b/src/gpu/GrTestUtils.cpp
index de840cc..13b4b19 100644
--- a/src/gpu/GrTestUtils.cpp
+++ b/src/gpu/GrTestUtils.cpp
@@ -248,6 +248,9 @@
     dashInfo.fIntervals = intervals.get();
     SkScalar sum = 0;
     for (int i = 0; i < dashInfo.fCount; i++) {
+    #if defined(SK_BUILD_FOR_IOS)
+        SkDebugf("&dashInfo.fIntervals[%d] = %p\n", i, &dashInfo.fIntervals[i]);
+    #endif
         dashInfo.fIntervals[i] = random->nextRangeScalar(SkDoubleToScalar(0.01),
                                                          SkDoubleToScalar(10.0));
         sum += dashInfo.fIntervals[i];