core: Don't debug native modules when TARGET_BUILD_TYPE==debug

Don't make the simulator default to debug mode.

Remove all global "debug" {C,CPP}FLAGS, which are no longer used.
diff --git a/core/product_config.mk b/core/product_config.mk
index 17cb413..7cfa5f4 100644
--- a/core/product_config.mk
+++ b/core/product_config.mk
@@ -256,13 +256,11 @@
     $(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_OTA_PUBLIC_KEYS))
 
 # ---------------------------------------------------------------
-# Force the simulator to be the simulator, and make BUILD_TYPE
-# default to debug.
+# Simulator overrides
 ifeq ($(TARGET_PRODUCT),sim)
+  # Tell the build system to turn on some special cases
+  # to deal with the simulator product.
   TARGET_SIMULATOR := true
-  ifeq (,$(strip $(TARGET_BUILD_TYPE)))
-    TARGET_BUILD_TYPE := debug
-  endif
   # dexpreopt doesn't work when building the simulator
   DISABLE_DEXPREOPT := true
 endif