Make ART compile with GCC -O0 again.

Tidy up InstructionSetFeatures so that it has a type hierarchy dependent on
architecture.
Add to instruction_set_test to warn when InstructionSetFeatures don't agree
with ones from system properties, AT_HWCAP and /proc/cpuinfo.
Clean-up class linker entry point logic to not return entry points but to
test whether the passed code is the particular entrypoint. This works around
image trampolines that replicate entrypoints.
Bug: 17993736

Change-Id: I5f4b49e88c3b02a79f9bee04f83395146ed7be23
diff --git a/test/Android.libarttest.mk b/test/Android.libarttest.mk
index 2d139a6..fd95038 100644
--- a/test/Android.libarttest.mk
+++ b/test/Android.libarttest.mk
@@ -69,7 +69,7 @@
     LOCAL_CLANG := $(ART_HOST_CLANG)
     LOCAL_CFLAGS := $(ART_HOST_CFLAGS) $(ART_HOST_DEBUG_CFLAGS)
     LOCAL_STATIC_LIBRARIES := libcutils
-    LOCAL_LDLIBS += -ldl -lpthread
+    LOCAL_LDLIBS := $(ART_HOST_LDLIBS) -ldl -lpthread
     ifeq ($(HOST_OS),linux)
       LOCAL_LDLIBS += -lrt
     endif