[flang][OpenMP] Remove OmpEndLoopDirective handles from code.

This directive is currently lowered as NOP.

Patch is an attempt upstream code from:
PR: flang-compiler#573

Reviewed By: kiranchandramohan, schweitz, clementval

Differential Revision: https://reviews.llvm.org/D100576

flang/include/flang/Lower/OpenMP.h

@@ -16,7 +16,6 @@
 namespace Fortran {
 namespace parser {
 struct OpenMPConstruct;
-struct OmpEndLoopDirective;
 } // namespace parser
 
 namespace lower {
@@ -30,9 +29,6 @@ struct Evaluation;
 void genOpenMPConstruct(AbstractConverter &, pft::Evaluation &,
                         const parser::OpenMPConstruct &);
 
-void genOpenMPEndLoop(AbstractConverter &, pft::Evaluation &,
-                      const parser::OmpEndLoopDirective &);
-
 } // namespace lower
 } // namespace Fortran
 

flang/lib/Lower/OpenMP.cpp

@@ -286,10 +286,3 @@ void Fortran::lower::genOpenMPConstruct(
       },
       ompConstruct.u);
 }
-
-void Fortran::lower::genOpenMPEndLoop(
-    Fortran::lower::AbstractConverter &converter,
-    Fortran::lower::pft::Evaluation &,
-    const Fortran::parser::OmpEndLoopDirective &) {
-  TODO(converter.getCurrentLocation(), "OmpEndLoopDirective");
-}