A64: Synchronize with r17441.

src/a64/regexp-macro-assembler-a64.h

Index: src/a64/regexp-macro-assembler-a64.h
diff --git a/src/a64/regexp-macro-assembler-a64.h b/src/a64/regexp-macro-assembler-a64.h
index e5a555ec7149f540ab79d2a1e05001e151fe3902..0f6b44b9fe97cdb48640858f1b13a2d788c04173 100644
--- a/src/a64/regexp-macro-assembler-a64.h
+++ b/src/a64/regexp-macro-assembler-a64.h
@@ -297,11 +297,6 @@ class RegExpMacroAssemblerA64: public NativeRegExpMacroAssembler {
   // are always 0..num_saved_registers_-1)
   int num_saved_registers_;
 
-  // Manage a small pre-allocated pool for writing label targets
-  // to for pushing backtrack addresses.
-  int backtrack_constant_pool_offset_;
-  int backtrack_constant_pool_capacity_;
-
   // Labels used internally.
   Label entry_label_;
   Label start_label_;