[interpreter] Bytecode register optimizer.

test/cctest/interpreter/bytecode_expectations/CallGlobal.golden

 #
 # Autogenerated by generate-bytecode-expectations.
 #
 
 ---
 pool type: string
 execute: yes
 wrap: no
 test function name: f
 
 ---
 snippet: "
   function t() { }
   function f() { return t(); }
   f();
 "
 frame size: 2
 parameter count: 1
-bytecode array length: 13
+bytecode array length: 15
 bytecodes: [
   /*   27 E> */ B(StackCheck),
-  /*   32 S> */ B(LdrUndefined), R(1),
-                B(LdrGlobal), U8(0), U8(3), R(0),
+  /*   32 S> */ B(LdaUndefined),
+                B(Star), R(1),
+                B(LdaGlobal), U8(0), U8(3),
+                B(Star), R(0),
   /*   39 E> */ B(Call), R(0), R(1), U8(1), U8(1),
   /*   44 S> */ B(Return),
 ]
 constant pool: [
   "t",
 ]
 handlers: [
 ]
 
 ---
 snippet: "
   function t(a, b, c) { }
   function f() { return t(1, 2, 3); }
   f();
 "
 frame size: 5
 parameter count: 1
-bytecode array length: 25
+bytecode array length: 27
 bytecodes: [
   /*   34 E> */ B(StackCheck),
-  /*   39 S> */ B(LdrUndefined), R(1),
-                B(LdrGlobal), U8(0), U8(3), R(0),
+  /*   39 S> */ B(LdaUndefined),
+                B(Star), R(1),
+                B(LdaGlobal), U8(0), U8(3),
+                B(Star), R(0),
                 B(LdaSmi), U8(1),
                 B(Star), R(2),
                 B(LdaSmi), U8(2),
                 B(Star), R(3),
                 B(LdaSmi), U8(3),
                 B(Star), R(4),
   /*   46 E> */ B(Call), R(0), R(1), U8(4), U8(1),
   /*   58 S> */ B(Return),
 ]
 constant pool: [
   "t",
 ]
 handlers: [
 ]