Remove DEX2OAT_DEPENDENCY which is the same as DEX2OAT.

Small cleanup to simplify the move of it into Soong.

Test: presubmits
Bug: 145934348
Change-Id: Ib60642168c8b27de9817539381177b8ee0c49f7c
diff --git a/build/Android.oat.mk b/build/Android.oat.mk
index 7c3e791..c6fe400 100644
--- a/build/Android.oat.mk
+++ b/build/Android.oat.mk
@@ -44,11 +44,10 @@
   core_image_name :=
   core_oat_name :=
   core_infix :=
-  core_dex2oat_dependency := $(DEX2OAT_DEPENDENCY)
+  core_dex2oat_dependency := $(DEX2OAT)
 
   ifeq ($(1),optimizing)
     core_compile_options += --compiler-backend=Optimizing
-    core_dex2oat_dependency := $(DEX2OAT)
   endif
   ifeq ($(1),interpreter)
     core_compile_options += --compiler-filter=quicken
@@ -157,13 +156,10 @@
   core_image_name :=
   core_oat_name :=
   core_infix :=
-  core_dex2oat_dependency := $(DEX2OAT_DEPENDENCY)
+  core_dex2oat_dependency := $(DEX2OAT)
 
   ifeq ($(1),optimizing)
     core_compile_options += --compiler-backend=Optimizing
-    # With the optimizing compiler, we want to rerun dex2oat whenever there is
-    # a dex2oat change to catch regressions early.
-    core_dex2oat_dependency := $(DEX2OAT)
   endif
   ifeq ($(1),interpreter)
     core_compile_options += --compiler-filter=quicken