[turbofan] remove dependence of InstructionBlock on BasicBlock

src/compiler/code-generator-impl.h

Index: src/compiler/code-generator-impl.h
diff --git a/src/compiler/code-generator-impl.h b/src/compiler/code-generator-impl.h
index 84309cc2d369bcec4050735a22cdfa1356e5f1d8..74233ac6fe1dcdc47f0371d0fa99349bfbbb5042 100644
--- a/src/compiler/code-generator-impl.h
+++ b/src/compiler/code-generator-impl.h
@@ -63,7 +63,7 @@ class InstructionOperandConverter {
 
   Label* InputLabel(size_t index) { return ToLabel(instr_->InputAt(index)); }
 
-  BasicBlock::RpoNumber InputRpo(size_t index) {
+  RpoNumber InputRpo(size_t index) {
     return ToRpoNumber(instr_->InputAt(index));
   }
 
@@ -85,7 +85,7 @@ class InstructionOperandConverter {
     return gen_->GetLabel(ToRpoNumber(op));
   }
 
-  BasicBlock::RpoNumber ToRpoNumber(InstructionOperand* op) {
+  RpoNumber ToRpoNumber(InstructionOperand* op) {
     return ToConstant(op).ToRpoNumber();
   }