Revert of Resolve references to "this" the same way as normal variables

src/mips64/lithium-codegen-mips64.cc

Index: src/mips64/lithium-codegen-mips64.cc
diff --git a/src/mips64/lithium-codegen-mips64.cc b/src/mips64/lithium-codegen-mips64.cc
index 002ad40cdb41199f2b65066c0fc41f57aff0f1d3..8562bec0fcb306fd4d4b10658ee741d94b6676e8 100644
--- a/src/mips64/lithium-codegen-mips64.cc
+++ b/src/mips64/lithium-codegen-mips64.cc
@@ -118,8 +118,8 @@
     // Sloppy mode functions and builtins need to replace the receiver with the
     // global proxy when called as functions (without an explicit receiver
     // object).
-    if (is_sloppy(info()->language_mode()) && info()->MayUseThis() &&
-        !info()->is_native() && info()->scope()->has_this_declaration()) {
+    if (is_sloppy(info_->language_mode()) && info()->MayUseThis() &&
+        !info_->is_native()) {
       Label ok;
       int receiver_offset = info_->scope()->num_parameters() * kPointerSize;
       __ LoadRoot(at, Heap::kUndefinedValueRootIndex);
@@ -192,9 +192,8 @@
     __ sd(v0, MemOperand(fp, StandardFrameConstants::kContextOffset));
     // Copy any necessary parameters into the context.
     int num_parameters = scope()->num_parameters();
-    int first_parameter = scope()->has_this_declaration() ? -1 : 0;
-    for (int i = first_parameter; i < num_parameters; i++) {
-      Variable* var = (i == -1) ? scope()->receiver() : scope()->parameter(i);
+    for (int i = 0; i < num_parameters; i++) {
+      Variable* var = scope()->parameter(i);
       if (var->IsContextSlot()) {
         int parameter_offset = StandardFrameConstants::kCallerSPOffset +
             (num_parameters - 1 - i) * kPointerSize;