[interpreter] Add support for scalable operands.

test/cctest/interpreter/bytecode_expectations/ContextVariables.golden

 #
 # Autogenerated by generate-bytecode-expectations.
 #
 
 ---
 pool type: mixed
 execute: yes
 wrap: yes
 
 ---
@@ skipping 20 matching lines @@
 snippet: "
   var a = 1; return function() { a = 2; };
 "
 frame size: 1
 parameter count: 1
 bytecode array length: 17
 bytecodes: [
   B(CallRuntime), U16(Runtime::kNewFunctionContext), R(closure), U8(1),
   B(PushContext), R(0),
   B(StackCheck),
-  B(LdaSmi8), U8(1),
+  B(LdaSmi), U8(1),
   B(StaContextSlot), R(context), U8(4),
   B(CreateClosure), U8(0), U8(0),
   B(Return),
 ]
 constant pool: [
   InstanceType::SHARED_FUNCTION_INFO_TYPE,
 ]
 handlers: [
 ]
 
 ---
 snippet: "
   var a = 1; var b = 2; return function() { a = 2; b = 3 };
 "
 frame size: 1
 parameter count: 1
 bytecode array length: 22
 bytecodes: [
   B(CallRuntime), U16(Runtime::kNewFunctionContext), R(closure), U8(1),
   B(PushContext), R(0),
   B(StackCheck),
-  B(LdaSmi8), U8(1),
+  B(LdaSmi), U8(1),
   B(StaContextSlot), R(context), U8(4),
-  B(LdaSmi8), U8(2),
+  B(LdaSmi), U8(2),
   B(StaContextSlot), R(context), U8(5),
   B(CreateClosure), U8(0), U8(0),
   B(Return),
 ]
 constant pool: [
   InstanceType::SHARED_FUNCTION_INFO_TYPE,
 ]
 handlers: [
 ]
 
@@ skipping 30 matching lines @@
 "
 frame size: 4
 parameter count: 1
 bytecode array length: 47
 bytecodes: [
   B(CallRuntime), U16(Runtime::kNewFunctionContext), R(closure), U8(1),
   B(PushContext), R(0),
   B(LdaTheHole),
   B(StaContextSlot), R(context), U8(4),
   B(StackCheck),
-  B(LdaSmi8), U8(1),
+  B(LdaSmi), U8(1),
   B(StaContextSlot), R(context), U8(4),
   B(LdaConstant), U8(0),
   B(Star), R(2),
   B(Ldar), R(closure),
   B(Star), R(3),
   B(CallRuntime), U16(Runtime::kPushBlockContext), R(2), U8(2),
   B(PushContext), R(1),
   B(LdaTheHole),
   B(StaContextSlot), R(context), U8(4),
-  B(LdaSmi8), U8(2),
+  B(LdaSmi), U8(2),
   B(StaContextSlot), R(context), U8(4),
   B(CreateClosure), U8(1), U8(0),
   B(PopContext), R(0),
   B(Return),
 ]
 constant pool: [
   InstanceType::FIXED_ARRAY_TYPE,
   InstanceType::SHARED_FUNCTION_INFO_TYPE,
 ]
 handlers: [
@@ skipping 250 matching lines @@
   var a245 = 0;
   var a246 = 0;
   var a247 = 0;
   var a248 = 0;
   eval();
   var b = 100;
   return b
 "
 frame size: 3
 parameter count: 1
-bytecode array length: 1042
+bytecode array length: 1046
 bytecodes: [
   B(CallRuntime), U16(Runtime::kNewFunctionContext), R(closure), U8(1),
   B(PushContext), R(0),
   B(Ldar), R(this),
   B(StaContextSlot), R(context), U8(4),
   B(CreateUnmappedArguments),
   B(StaContextSlot), R(context), U8(5),
   B(Ldar), R(new_target),
   B(StaContextSlot), R(context), U8(6),
   B(StackCheck),
@@ skipping 493 matching lines @@
   B(StaContextSlot), R(context), U8(253),
   B(LdaZero),
   B(StaContextSlot), R(context), U8(254),
   B(LdaZero),
   B(StaContextSlot), R(context), U8(255),
   B(LdaUndefined),
   B(Star), R(2),
   B(LdaGlobal), U8(0), U8(1),
   B(Star), R(1),
   B(Call), R(1), R(2), U8(1), U8(0),
-  B(LdaSmi8), U8(100),
-  B(StaContextSlotWide), R(context), U16(256),
-  B(LdaContextSlotWide), R(context), U16(256),
+  B(LdaSmi), U8(100),
+  B(Wide), B(StaContextSlot), R16(context), U16(256),
+  B(Wide), B(LdaContextSlot), R16(context), U16(256),
   B(Return),
 ]
 constant pool: [
   InstanceType::ONE_BYTE_INTERNALIZED_STRING_TYPE,
 ]
 handlers: [
 ]