PREOPT compiles using dex2oatd so don't emit debug instructions.

Change-Id: I8d2ab8d956ad0ce313928918c658d49f490ad081
diff --git a/compiler/optimizing/code_generator_arm.cc b/compiler/optimizing/code_generator_arm.cc
index 123f690..0a069a7 100644
--- a/compiler/optimizing/code_generator_arm.cc
+++ b/compiler/optimizing/code_generator_arm.cc
@@ -903,10 +903,6 @@
 
 void InstructionCodeGeneratorARM::VisitExit(HExit* exit) {
   UNUSED(exit);
-  if (kIsDebugBuild) {
-    __ Comment("Unreachable");
-    __ bkpt(0);
-  }
 }
 
 void LocationsBuilderARM::VisitIf(HIf* if_instr) {
diff --git a/compiler/optimizing/code_generator_arm64.cc b/compiler/optimizing/code_generator_arm64.cc
index c48cab4..aeec5dd 100644
--- a/compiler/optimizing/code_generator_arm64.cc
+++ b/compiler/optimizing/code_generator_arm64.cc
@@ -1596,10 +1596,6 @@
 
 void InstructionCodeGeneratorARM64::VisitExit(HExit* exit) {
   UNUSED(exit);
-  if (kIsDebugBuild) {
-    down_cast<Arm64Assembler*>(GetAssembler())->Comment("Unreachable");
-    __ Brk(__LINE__);    // TODO: Introduce special markers for such code locations.
-  }
 }
 
 void LocationsBuilderARM64::VisitFloatConstant(HFloatConstant* constant) {
diff --git a/compiler/optimizing/code_generator_x86.cc b/compiler/optimizing/code_generator_x86.cc
index 1db1600..754dd10 100644
--- a/compiler/optimizing/code_generator_x86.cc
+++ b/compiler/optimizing/code_generator_x86.cc
@@ -812,10 +812,6 @@
 
 void InstructionCodeGeneratorX86::VisitExit(HExit* exit) {
   UNUSED(exit);
-  if (kIsDebugBuild) {
-    __ Comment("Unreachable");
-    __ int3();
-  }
 }
 
 void LocationsBuilderX86::VisitIf(HIf* if_instr) {
diff --git a/compiler/optimizing/code_generator_x86_64.cc b/compiler/optimizing/code_generator_x86_64.cc
index 90d87d4..dbd7c9e 100644
--- a/compiler/optimizing/code_generator_x86_64.cc
+++ b/compiler/optimizing/code_generator_x86_64.cc
@@ -749,10 +749,6 @@
 
 void InstructionCodeGeneratorX86_64::VisitExit(HExit* exit) {
   UNUSED(exit);
-  if (kIsDebugBuild) {
-    __ Comment("Unreachable");
-    __ int3();
-  }
 }
 
 void LocationsBuilderX86_64::VisitIf(HIf* if_instr) {