Make SkSmallAllocator obey the RAII invariants and be expandable

src/core/SkRasterPipelineBlitter.cpp

Index: src/core/SkRasterPipelineBlitter.cpp
diff --git a/src/core/SkRasterPipelineBlitter.cpp b/src/core/SkRasterPipelineBlitter.cpp
index 2cd84f0ede5d78687341d5490b3866e06b83372f..5a7ee67c9b0c11c75784791498ebdd5f9f3eabea 100644
--- a/src/core/SkRasterPipelineBlitter.cpp
+++ b/src/core/SkRasterPipelineBlitter.cpp
@@ -93,8 +93,7 @@ SkBlitter* SkRasterPipelineBlitter::Create(const SkPixmap& dst,
             SkPM4f_from_SkColor(paint.getColor(), dst.colorSpace()));
 
     auto earlyOut = [&] {
-        blitter->~SkRasterPipelineBlitter();
-        alloc->freeLast();
+        alloc->deleteLast();
         return nullptr;
     };