Add ResTable_sparseTypeEntry support

Benchmarks on bullhead-userdebug show that there is a negligent
performance impact when using sparse entries on a 30% loaded
sparse type of 1000 resources.

Benchmark                                             Time           CPU Iterations
-----------------------------------------------------------------------------------
BM_SparseEntryGetResourceSparseLarge                255 ns        254 ns    2751408
BM_SparseEntryGetResourceNotSparseLarge             254 ns        254 ns    2756534

Bug: 27381711
Test: make libandroidfw_tests aapt2_tests
Change-Id: I051ea22f2f6b2bc3696e446adc9e2a34be18009f
diff --git a/libs/androidfw/tests/TestHelpers.h b/libs/androidfw/tests/TestHelpers.h
index a11ea84..ec78b2a 100644
--- a/libs/androidfw/tests/TestHelpers.h
+++ b/libs/androidfw/tests/TestHelpers.h
@@ -19,6 +19,7 @@
 
 #include <ostream>
 #include <string>
+#include <vector>
 
 #include "androidfw/ResourceTypes.h"
 #include "gtest/gtest.h"