Drop IsPregenerated() and allow_stub_calls flag.

test/cctest/test-code-stubs-x64.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Rrdistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Rrdistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Rrdistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 34 matching lines @@
                                               Register source_reg,
                                               Register destination_reg) {
   // Allocate an executable page of memory.
   size_t actual_size;
   byte* buffer = static_cast<byte*>(OS::Allocate(Assembler::kMinimalBufferSize,
                                                    &actual_size,
                                                    true));
   CHECK(buffer);
   HandleScope handles(isolate);
   MacroAssembler assm(isolate, buffer, static_cast<int>(actual_size));
-  assm.set_allow_stub_calls(false);
   int offset =
     source_reg.is(rsp) ? 0 : (HeapNumber::kValueOffset - kSmiTagSize);
   DoubleToIStub stub(source_reg, destination_reg, offset, true);
   byte* start = stub.GetCode(isolate)->instruction_start();
 
   __ push(rbx);
   __ push(rcx);
   __ push(rdx);
   __ push(rsi);
   __ push(rdi);
@@ skipping 78 matching lines @@
 
   for (size_t s = 0; s < sizeof(source_registers) / sizeof(Register); s++) {
     for (size_t d = 0; d < sizeof(dest_registers) / sizeof(Register); d++) {
       RunAllTruncationTests(
           MakeConvertDToIFuncTrampoline(isolate,
                                         source_registers[s],
                                         dest_registers[d]));
     }
   }
 }