Revert "Use dx.jar directly"

This reverts commit e37a3c959a833b9979f7e820cb037711c7453c16.

Reason for revert: breaks art test runner

Change-Id: Ice0cd3020ddec7f31eb789867a45f047a75a05d0
diff --git a/core/config.mk b/core/config.mk
index dba2555..f839d3d 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -499,11 +499,6 @@
 
 USE_PREBUILT_SDK_TOOLS_IN_PLACE := true
 
-# TODO(ccross): remove this once the build server no longer references it
-ifdef DX_ALT_JAR
-DX_JAR := DX_ALT_JAR
-endif
-
 #
 # Tools that are prebuilts for TARGET_BUILD_APPS
 #
@@ -511,16 +506,24 @@
   AIDL := $(HOST_OUT_EXECUTABLES)/aidl
   AAPT := $(HOST_OUT_EXECUTABLES)/aapt
   AAPT2 := $(HOST_OUT_EXECUTABLES)/aapt2
-  DX_JAR ?= $(HOST_OUT_JAVA_LIBRARIES)/dx.jar
   MAINDEXCLASSES := $(HOST_OUT_EXECUTABLES)/mainDexClasses
   SIGNAPK_JAR := $(HOST_OUT_JAVA_LIBRARIES)/signapk$(COMMON_JAVA_PACKAGE_SUFFIX)
   SIGNAPK_JNI_LIBRARY_PATH := $(HOST_OUT_SHARED_LIBRARIES)
   ZIPALIGN := $(HOST_OUT_EXECUTABLES)/zipalign
+
+  ifndef DX_ALT_JAR
+    DX := $(HOST_OUT_EXECUTABLES)/dx
+    DX_COMMAND := $(DX) -JXms16M -JXmx2048M
+  else
+    DX := $(DX_ALT_JAR)
+    DX_COMMAND := $(JAVA) -Xms16M -Xmx2048M -jar $(DX)
+  endif
 else # TARGET_BUILD_APPS || TARGET_BUILD_PDK
   AIDL := $(prebuilt_sdk_tools_bin)/aidl
   AAPT := $(prebuilt_sdk_tools_bin)/aapt
   AAPT2 := $(prebuilt_sdk_tools_bin)/aapt2
-  DX_JAR ?= $(prebuilt_sdk_tools)/lib/dx.jar
+  DX := $(prebuilt_sdk_tools)/dx
+  DX_COMMAND := $(DX) -JXms16M -JXmx2048M
   MAINDEXCLASSES := $(prebuilt_sdk_tools)/mainDexClasses
   ZIPALIGN := $(prebuilt_sdk_tools_bin)/zipalign
   SIGNAPK_JAR := $(prebuilt_sdk_tools)/lib/signapk$(COMMON_JAVA_PACKAGE_SUFFIX)
@@ -558,16 +561,6 @@
 ZIP2ZIP := $(SOONG_HOST_OUT_EXECUTABLES)/zip2zip
 ZIPTIME := $(prebuilt_build_tools_bin)/ziptime
 
-# DX can be overriden on the command line
-ifndef DX
-#TODO: use a smaller -Xmx value for most libraries;
-#      only core.jar and framework.jar need a heap this big.
-DX := $(JAVA) -Xms16M -Xmx2048M -jar $(DX_JAR)
-DX_DEPS := $(DX_JAR)
-else
-DX_DEPS ?= $(DX)
-endif
-
 # ---------------------------------------------------------------
 # Generic tools.
 JACK := $(HOST_OUT_EXECUTABLES)/jack