Keep the symbol table in the shared libraries.

In order to allow the unwinder code to have meaningful names for
art functions, leave the symbol table.

Here are the size increases:

Platform    Size Increase
--------    -------------
arm         ~631K
arm64       ~631K
mips        ~424K
x86         ~565K
x86_64      ~565K

Bug: 12958251
Change-Id: Ib8bf11bef648f8296f4d6544f7b2af0d7f969ad8
diff --git a/runtime/Android.mk b/runtime/Android.mk
index e8224cd..c8d294a 100644
--- a/runtime/Android.mk
+++ b/runtime/Android.mk
@@ -436,6 +436,11 @@
   endif
 
   ifeq ($$(art_target_or_host),target)
+    ifneq ($$(art_ndebug_or_debug),debug)
+      # Leave the symbols in the shared library so that stack unwinders can
+      # produce meaningful name resolution.
+      LOCAL_STRIP_MODULE := keep_symbols
+    endif
     include $(BUILD_SHARED_LIBRARY)
   else # host
     include $(BUILD_HOST_SHARED_LIBRARY)