Move libdexfile out of runtime

Move the files out of runtime, leaving unfortunate dependences still
there on runtime/base (for the moment).  Also separates the build logic
into two Android.bp files.

Bug: 22322814
Test: make -j 50 test-art-host
Change-Id: Ib0a1cda833b29ecfa4c8c50f23fab89ba666f491
diff --git a/build/Android.gtest.mk b/build/Android.gtest.mk
index d6c87b6..59a1046 100644
--- a/build/Android.gtest.mk
+++ b/build/Android.gtest.mk
@@ -333,6 +333,7 @@
     art_dexoptanalyzer_tests \
     art_hiddenapi_tests \
     art_imgdiag_tests \
+    art_libdexfile_tests \
     art_oatdump_tests \
     art_patchoat_tests \
     art_profman_tests \