Convert SkWriter32 to use an SkTDArray for its internal storage.

tests/PathTest.cpp

Index: tests/PathTest.cpp
diff --git a/tests/PathTest.cpp b/tests/PathTest.cpp
index 3f07ae04bc5aa87396bf512c928ae0ec75ef6600..063f05d5ed95f329110419a008379fd927be82a1 100644
--- a/tests/PathTest.cpp
+++ b/tests/PathTest.cpp
@@ -1838,7 +1838,7 @@ static void test_isNestedRects(skiatest::Reporter* reporter) {
 
 static void write_and_read_back(skiatest::Reporter* reporter,
                                 const SkPath& p) {
-    SkWriter32 writer(100);
+    SkWriter32 writer;
     writer.writePath(p);
     size_t size = writer.bytesWritten();
     SkAutoMalloc storage(size);