Revert of Internalize strings in-place

src/x87/codegen-x87.cc

Index: src/x87/codegen-x87.cc
diff --git a/src/x87/codegen-x87.cc b/src/x87/codegen-x87.cc
index 846b2987e1637f84deb44dffc92326f7b71f9e5b..a2bba1dcd7c565c0544a8f6d6a3903fddefb1d06 100644
--- a/src/x87/codegen-x87.cc
+++ b/src/x87/codegen-x87.cc
@@ -228,12 +228,9 @@
   __ j(zero, &check_sequential, Label::kNear);
 
   // Dispatch on the indirect string shape: slice or cons.
-  Label cons_string, thin_string;
-  __ and_(result, Immediate(kStringRepresentationMask));
-  __ cmp(result, Immediate(kConsStringTag));
-  __ j(equal, &cons_string, Label::kNear);
-  __ cmp(result, Immediate(kThinStringTag));
-  __ j(equal, &thin_string, Label::kNear);
+  Label cons_string;
+  __ test(result, Immediate(kSlicedNotConsMask));
+  __ j(zero, &cons_string, Label::kNear);
 
   // Handle slices.
   Label indirect_string_loaded;
@@ -241,11 +238,6 @@
   __ SmiUntag(result);
   __ add(index, result);
   __ mov(string, FieldOperand(string, SlicedString::kParentOffset));
-  __ jmp(&indirect_string_loaded, Label::kNear);
-
-  // Handle thin strings.
-  __ bind(&thin_string);
-  __ mov(string, FieldOperand(string, ThinString::kActualOffset));
   __ jmp(&indirect_string_loaded, Label::kNear);
 
   // Handle cons strings.