Indirectly dispatch all backtracking jumps through the same block.

runtime/vm/regexp.h

Index: runtime/vm/regexp.h
diff --git a/runtime/vm/regexp.h b/runtime/vm/regexp.h
index 2675aaaf5a51ffe9ebd0fb29d4510ae1095abcc9..81a6454d0748dcbe079032bf7e2792203b19cce6 100644
--- a/runtime/vm/regexp.h
+++ b/runtime/vm/regexp.h
@@ -1372,22 +1372,22 @@ class RegExpEngine: public AllStatic {
  public:
   struct CompilationResult {
     explicit CompilationResult(const char* error_message)
-        : macro_assembler(NULL),
+        : backtrack_goto(NULL),
           graph_entry(NULL),
           num_blocks(-1),
           num_stack_locals(-1),
           error_message(error_message) {}
-    CompilationResult(IRRegExpMacroAssembler* macro_assembler,
+    CompilationResult(IndirectGotoInstr* backtrack_goto,
                       GraphEntryInstr* graph_entry,
                       intptr_t num_blocks,
                       intptr_t num_stack_locals)
-      : macro_assembler(macro_assembler),
+      : backtrack_goto(backtrack_goto),
         graph_entry(graph_entry),
         num_blocks(num_blocks),
         num_stack_locals(num_stack_locals),
         error_message(NULL) {}
 
-    IRRegExpMacroAssembler* macro_assembler;
+    IndirectGotoInstr* backtrack_goto;
     GraphEntryInstr* graph_entry;
     const intptr_t num_blocks;
     const intptr_t num_stack_locals;