Remove the barely used macro assemblers after merging their contents to the base

runtime/vm/intermediate_language_x64.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_X64.
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/intermediate_language.h"
 
 #include "lib/error.h"
@@ skipping 2301 matching lines @@
 };
 
 
 void BoxDoubleInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   BoxDoubleSlowPath* slow_path = new BoxDoubleSlowPath(this);
   compiler->AddSlowPathCode(slow_path);
 
   Register out_reg = locs()->out().reg();
   XmmRegister value = locs()->in(0).fpu_reg();
 
-  AssemblerMacros::TryAllocate(compiler->assembler(),
-                               compiler->double_class(),
-                               slow_path->entry_label(),
-                               Assembler::kFarJump,
-                               out_reg);
+  __ TryAllocate(compiler->double_class(),
+                 slow_path->entry_label(),
+                 Assembler::kFarJump,
+                 out_reg);
   __ Bind(slow_path->exit_label());
   __ movsd(FieldAddress(out_reg, Double::value_offset()), value);
 }
 
 
 LocationSummary* UnboxDoubleInstr::MakeLocationSummary() const {
   const intptr_t kNumInputs = 1;
   const intptr_t kNumTemps = 0;
   LocationSummary* summary =
       new LocationSummary(kNumInputs, kNumTemps, LocationSummary::kNoCall);
@@ skipping 823 matching lines @@
                          PcDescriptors::kOther,
                          locs());
   __ Drop(2);  // Discard type arguments and receiver.
 }
 
 }  // namespace dart
 
 #undef __
 
 #endif  // defined TARGET_ARCH_X64