[Proxies] Support constructable proxy as new.target (reland)

src/mips/builtins-mips.cc

Index: src/mips/builtins-mips.cc
diff --git a/src/mips/builtins-mips.cc b/src/mips/builtins-mips.cc
index c96722fafedd2a0d4ba502f78202f5041d2baed6..187d3403ab2ef850bc1f3c426dbd2c7f583dfbaf 100644
--- a/src/mips/builtins-mips.cc
+++ b/src/mips/builtins-mips.cc
@@ -1769,10 +1769,9 @@ void Builtins::Generate_ConstructFunction(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- a0 : the number of arguments (not including the receiver)
   //  -- a1 : the constructor to call (checked to be a JSFunction)
-  //  -- a3 : the new target (checked to be a JSFunction)
+  //  -- a3 : the new target (checked to be a constructor)
   // -----------------------------------
   __ AssertFunction(a1);
-  __ AssertFunction(a3);
 
   // Calling convention for function specific ConstructStubs require
   // a2 to contain either an AllocationSite or undefined.