Added test for ifunc support in dynamic linker.

ifuncs now work in i386 and x86_64 when called in the same library as
well as in a different library.

Bug:6657325
Change-Id: Ic0c48b1b0a76cb90f36c20c79f68294cc3fd44a1
diff --git a/linker/linker_debug.h b/linker/linker_debug.h
index 3faa38e..0c7a784 100644
--- a/linker/linker_debug.h
+++ b/linker/linker_debug.h
@@ -42,6 +42,7 @@
 #define TRACE_DEBUG          1
 #define DO_TRACE_LOOKUP      1
 #define DO_TRACE_RELO        1
+#define DO_TRACE_IFUNC       1
 #define TIMING               0
 #define STATS                0
 #define COUNT_PAGES          0