[ignition] Add bytecodes for loads/stores in the current context

test/cctest/interpreter/bytecode_expectations/ContextParameters.golden

 #
 # Autogenerated by generate-bytecode-expectations.
 #
 
 ---
 wrap: no
 test function name: f
 
 ---
 snippet: "
   function f(arg1) { return function() { arg1 = 2; }; }
   f();
 "
 frame size: 1
 parameter count: 2
-bytecode array length: 15
+bytecode array length: 13
 bytecodes: [
                 B(CreateFunctionContext), U8(1),
                 B(PushContext), R(0),
                 B(Ldar), R(arg0),
-                B(StaContextSlot), R(context), U8(4), U8(0),
+                B(StaCurrentContextSlot), U8(4),
   /*   10 E> */ B(StackCheck),
   /*   19 S> */ B(CreateClosure), U8(0), U8(2),
   /*   52 S> */ B(Return),
 ]
 constant pool: [
   SHARED_FUNCTION_INFO_TYPE,
 ]
 handlers: [
 ]
 
 ---
 snippet: "
   function f(arg1) { var a = function() { arg1 = 2; }; return arg1; }
   f();
 "
 frame size: 2
 parameter count: 2
-bytecode array length: 21
+bytecode array length: 17
 bytecodes: [
                 B(CreateFunctionContext), U8(1),
                 B(PushContext), R(1),
                 B(Ldar), R(arg0),
-                B(StaContextSlot), R(context), U8(4), U8(0),
+                B(StaCurrentContextSlot), U8(4),
   /*   10 E> */ B(StackCheck),
   /*   27 S> */ B(CreateClosure), U8(0), U8(2),
                 B(Star), R(0),
-  /*   53 S> */ B(LdaContextSlot), R(context), U8(4), U8(0),
+  /*   53 S> */ B(LdaCurrentContextSlot), U8(4),
   /*   66 S> */ B(Return),
 ]
 constant pool: [
   SHARED_FUNCTION_INFO_TYPE,
 ]
 handlers: [
 ]
 
 ---
 snippet: "
   function f(a1, a2, a3, a4) { return function() { a1 = a3; }; }
   f();
 "
 frame size: 1
 parameter count: 5
-bytecode array length: 21
+bytecode array length: 17
 bytecodes: [
                 B(CreateFunctionContext), U8(2),
                 B(PushContext), R(0),
                 B(Ldar), R(arg0),
-                B(StaContextSlot), R(context), U8(5), U8(0),
+                B(StaCurrentContextSlot), U8(5),
                 B(Ldar), R(arg2),
-                B(StaContextSlot), R(context), U8(4), U8(0),
+                B(StaCurrentContextSlot), U8(4),
   /*   10 E> */ B(StackCheck),
   /*   29 S> */ B(CreateClosure), U8(0), U8(2),
   /*   61 S> */ B(Return),
 ]
 constant pool: [
   SHARED_FUNCTION_INFO_TYPE,
 ]
 handlers: [
 ]
 
 ---
 snippet: "
   function f() { var self = this; return function() { self = 2; }; }
   f();
 "
 frame size: 1
 parameter count: 1
-bytecode array length: 15
+bytecode array length: 13
 bytecodes: [
                 B(CreateFunctionContext), U8(1),
                 B(PushContext), R(0),
   /*   10 E> */ B(StackCheck),
   /*   26 S> */ B(Ldar), R(this),
-  /*   26 E> */ B(StaContextSlot), R(context), U8(4), U8(0),
+  /*   26 E> */ B(StaCurrentContextSlot), U8(4),
   /*   32 S> */ B(CreateClosure), U8(0), U8(2),
   /*   65 S> */ B(Return),
 ]
 constant pool: [
   SHARED_FUNCTION_INFO_TYPE,
 ]
 handlers: [
 ]