Move precompilation-related flags to flags list.

runtime/vm/code_descriptors.cc

Index: runtime/vm/code_descriptors.cc
diff --git a/runtime/vm/code_descriptors.cc b/runtime/vm/code_descriptors.cc
index a286a044cca111565289eee13814bea270ed26ce..e5fa106746c9ca756c77762b250baf89d9617c61 100644
--- a/runtime/vm/code_descriptors.cc
+++ b/runtime/vm/code_descriptors.cc
@@ -6,8 +6,6 @@
 
 namespace dart {
 
-DECLARE_FLAG(bool, precompilation);
-
 void DescriptorList::AddDescriptor(RawPcDescriptors::Kind kind,
                                    intptr_t pc_offset,
                                    intptr_t deopt_id,
@@ -18,7 +16,7 @@ void DescriptorList::AddDescriptor(RawPcDescriptors::Kind kind,
          (deopt_id != Thread::kNoDeoptId));
 
   // When precompiling, we only use pc descriptors for exceptions.
-  if (!FLAG_precompilation || try_index != -1) {
+  if (!FLAG_precompiled_mode || try_index != -1) {
     intptr_t merged_kind_try =
         RawPcDescriptors::MergedKindTry::Encode(kind, try_index);