[interpreter] Add support for scalable operands.

test/cctest/interpreter/bytecode_expectations/Parameters.golden

 #
 # Autogenerated by generate-bytecode-expectations.
 #
 
 ---
 pool type: mixed
 execute: yes
 wrap: no
 test function name: f
 
@@ skipping 90 matching lines @@
 ---
 snippet: "
   function f(arg1) { arg1 = 1; }
   f();
 "
 frame size: 0
 parameter count: 2
 bytecode array length: 7
 bytecodes: [
   B(StackCheck),
-  B(LdaSmi8), U8(1),
+  B(LdaSmi), U8(1),
   B(Star), R(arg0),
   B(LdaUndefined),
   B(Return),
 ]
 constant pool: [
 ]
 handlers: [
 ]
 
 ---
 snippet: "
   function f(arg1, arg2, arg3, arg4) { arg2 = 1; }
   f();
 "
 frame size: 0
 parameter count: 5
 bytecode array length: 7
 bytecodes: [
   B(StackCheck),
-  B(LdaSmi8), U8(1),
+  B(LdaSmi), U8(1),
   B(Star), R(arg1),
   B(LdaUndefined),
   B(Return),
 ]
 constant pool: [
 ]
 handlers: [
 ]