[interpreter] Faster and fewer flushes in register optimizer.

test/cctest/interpreter/bytecode_expectations/ClassAndSuperClass.golden

 #
 # Autogenerated by generate-bytecode-expectations.
 #
 
 ---
 pool type: mixed
 execute: yes
 wrap: no
 test function name: test
 
@@ skipping 11 matching lines @@
     test();
   })();
 "
 frame size: 7
 parameter count: 1
 bytecode array length: 55
 bytecodes: [
                 B(Mov), R(closure), R(0),
   /*   99 E> */ B(StackCheck),
   /*  104 S> */ B(Nop),
-  /*  111 E> */ B(Ldar), R(closure),
-                B(Mov), R(this), R(3),
+  /*  111 E> */ B(Mov), R(this), R(3),
+                B(Ldar), R(closure),
                 B(JumpIfNotHole), U8(11),
                 B(LdaConstant), U8(0),
                 B(Star), R(6),
                 B(CallRuntime), U16(Runtime::kThrowReferenceError), R(6), U8(1),
                 B(Star), R(6),
   /*  111 E> */ B(LdaConstant), U8(1),
                 B(LdrKeyedProperty), R(6), U8(3), R(4),
                 B(LdaConstant), U8(2),
                 B(Star), R(5),
                 B(CallRuntime), U16(Runtime::kLoadFromSuper), R(3), U8(3),
@@ skipping 28 matching lines @@
     test();
   })();
 "
 frame size: 6
 parameter count: 1
 bytecode array length: 77
 bytecodes: [
                 B(Mov), R(closure), R(0),
   /*  125 E> */ B(StackCheck),
   /*  130 S> */ B(Nop),
-  /*  130 E> */ B(Ldar), R(closure),
-                B(Mov), R(this), R(1),
+  /*  130 E> */ B(Mov), R(this), R(1),
+                B(Ldar), R(closure),
                 B(JumpIfNotHole), U8(11),
                 B(LdaConstant), U8(0),
                 B(Star), R(5),
                 B(CallRuntime), U16(Runtime::kThrowReferenceError), R(5), U8(1),
                 B(Star), R(5),
   /*  130 E> */ B(LdaConstant), U8(1),
                 B(LdrKeyedProperty), R(5), U8(1), R(2),
                 B(LdaConstant), U8(2),
                 B(Star), R(3),
                 B(LdaSmi), U8(2),
   /*  138 E> */ B(Star), R(4),
                 B(CallRuntime), U16(Runtime::kStoreToSuper_Strict), R(1), U8(4),
   /*  143 S> */ B(Nop),
-  /*  150 E> */ B(Ldar), R(0),
-                B(Mov), R(this), R(1),
+  /*  150 E> */ B(Mov), R(this), R(1),
+                B(Ldar), R(0),
                 B(JumpIfNotHole), U8(11),
                 B(LdaConstant), U8(0),
                 B(Star), R(4),
                 B(CallRuntime), U16(Runtime::kThrowReferenceError), R(4), U8(1),
                 B(Star), R(4),
   /*  150 E> */ B(LdaConstant), U8(1),
                 B(LdrKeyedProperty), R(4), U8(3), R(2),
                 B(LdaConstant), U8(2),
                 B(Star), R(3),
                 B(CallRuntime), U16(Runtime::kLoadFromSuper), R(1), U8(3),
@@ skipping 134 matching lines @@
 ]
 constant pool: [
   InstanceType::ONE_BYTE_INTERNALIZED_STRING_TYPE,
   InstanceType::ONE_BYTE_INTERNALIZED_STRING_TYPE,
   InstanceType::ONE_BYTE_INTERNALIZED_STRING_TYPE,
   InstanceType::ONE_BYTE_INTERNALIZED_STRING_TYPE,
 ]
 handlers: [
 ]