Only add libdl dependency for ASan/TSan on target.

Only sanitizers that intercept stuff need that. For example,
SafeStack does not, and I think UBSan too.

Bug: 27729263
Change-Id: I413cd46cc6c6914a363a3c53da7954beacd8f0d8

core/config_sanitizers.mk

@@ -101,9 +101,11 @@ ifneq ($(my_sanitize),)
       my_cflags += -fsanitize-trap=all
       my_cflags += -ftrap-function=abort
     endif
+    ifneq ($(filter address thread,$(my_sanitize)),)
       my_shared_libraries += libdl
     endif
   endif
+endif
 
 # If local or global modules need ASAN, add linker flags.
 ifneq ($(filter address,$(my_global_sanitize) $(my_sanitize)),)