[interpreter] Bytecode register optimizer.

test/cctest/interpreter/bytecode_expectations/ContextVariables.golden

Index: test/cctest/interpreter/bytecode_expectations/ContextVariables.golden
diff --git a/test/cctest/interpreter/bytecode_expectations/ContextVariables.golden b/test/cctest/interpreter/bytecode_expectations/ContextVariables.golden
index 462fb9e5f317e334a79a02be2fb09955c6f44c7e..793d3e12a6abdef300e0e2daf5fe8d074e133ca6 100644
--- a/test/cctest/interpreter/bytecode_expectations/ContextVariables.golden
+++ b/test/cctest/interpreter/bytecode_expectations/ContextVariables.golden
@@ -79,12 +79,13 @@ snippet: "
 "
 frame size: 3
 parameter count: 1
-bytecode array length: 24
+bytecode array length: 25
 bytecodes: [
                 B(CallRuntime), U16(Runtime::kNewFunctionContext), R(closure), U8(1),
                 B(PushContext), R(0),
   /*   30 E> */ B(StackCheck),
-  /*   41 S> */ B(LdrUndefined), R(2),
+  /*   41 S> */ B(LdaUndefined),
+                B(Star), R(2),
                 B(CreateClosure), U8(0), U8(0),
                 B(Star), R(1),
   /*   64 E> */ B(Call), R(1), R(2), U8(1), U8(1),
@@ -105,7 +106,7 @@ snippet: "
 "
 frame size: 4
 parameter count: 1
-bytecode array length: 47
+bytecode array length: 46
 bytecodes: [
                 B(CallRuntime), U16(Runtime::kNewFunctionContext), R(closure), U8(1),
                 B(PushContext), R(0),
@@ -116,8 +117,7 @@ bytecodes: [
   /*   56 E> */ B(StaContextSlot), R(context), U8(4),
                 B(LdaConstant), U8(0),
                 B(Star), R(2),
-                B(Ldar), R(closure),
-                B(Star), R(3),
+                B(Mov), R(closure), R(3),
                 B(CallRuntime), U16(Runtime::kPushBlockContext), R(2), U8(2),
                 B(PushContext), R(1),
                 B(LdaTheHole),
@@ -393,7 +393,7 @@ snippet: "
 "
 frame size: 3
 parameter count: 1
-bytecode array length: 1044
+bytecode array length: 1046
 bytecodes: [
                 B(CallRuntime), U16(Runtime::kNewFunctionContext), R(closure), U8(1),
                 B(PushContext), R(0),
@@ -902,8 +902,10 @@ bytecodes: [
   /* 3407 E> */ B(StaContextSlot), R(context), U8(254),
   /* 3421 S> */ B(LdaZero),
   /* 3421 E> */ B(StaContextSlot), R(context), U8(255),
-  /* 3424 S> */ B(LdrUndefined), R(2),
-  /* 3424 E> */ B(LdrGlobal), U8(0), U8(1), R(1),
+  /* 3424 S> */ B(LdaUndefined),
+                B(Star), R(2),
+  /* 3424 E> */ B(LdaGlobal), U8(0), U8(1),
+                B(Star), R(1),
   /* 3424 E> */ B(Call), R(1), R(2), U8(1), U8(0),
   /* 3440 S> */ B(LdaSmi), U8(100),
   /* 3440 E> */ B(Wide), B(StaContextSlot), R16(context), U16(256),