Add missing test files to compile.

Bug: 23762183

Test: Ran unit tests.
Change-Id: I8ac43517231d88c68c288800d8ed286daa57bce1
diff --git a/libunwindstack/Android.bp b/libunwindstack/Android.bp
index 5445f6e..03a9a54 100644
--- a/libunwindstack/Android.bp
+++ b/libunwindstack/Android.bp
@@ -103,11 +103,13 @@
         "tests/MapInfoCreateMemoryTest.cpp",
         "tests/MapInfoGetElfTest.cpp",
         "tests/MapsTest.cpp",
+        "tests/MemoryBuffer.cpp",
         "tests/MemoryFake.cpp",
         "tests/MemoryFileTest.cpp",
         "tests/MemoryLocalTest.cpp",
         "tests/MemoryRangeTest.cpp",
         "tests/MemoryRemoteTest.cpp",
+        "tests/MemoryTest.cpp",
         "tests/RegsTest.cpp",
         "tests/SymbolsTest.cpp",
     ],