[FLANG]Build failed after synchro with the upstream

```
[ 82%] Building CXX object tools/flang/lib/Evaluate/CMakeFiles/FortranEvaluate.dir/fold-character.cpp.o
In file included from /home/users/laos/llvm-flang/src/llvm-project/flang/lib/Evaluate/fold-character.cpp:10:
/home/users/laos/llvm-flang/src/llvm-project/flang/lib/Evaluate/fold-reduction.h:18:16: error: unused function template 'FoldDotProduct' [-Werror,-Wunused-template]
18 | static Expr FoldDotProduct(
| ^~~~~~~~~~~~~~
/home/users/laos/llvm-flang/src/llvm-project/flang/lib/Evaluate/fold-reduction.h:312:16: error: unused function template 'FoldProduct' [-Werror,-Wunused-template]
312 | static Expr FoldProduct(
| ^~~~~~~~~~~
/home/users/laos/llvm-flang/src/llvm-project/flang/lib/Evaluate/fold-reduction.h:374:16: error: unused function template 'FoldSum' [-Werror,-Wunused-template]
374 | static Expr FoldSum(FoldingContext &context, FunctionRef &&ref) {
| ^~~~~~~
3 errors generated.
gmake[2]: *** [tools/flang/lib/Evaluate/CMakeFiles/FortranEvaluate.dir/build.make:224: tools/flang/lib/Evaluate/CMakeFiles/FortranEvaluate.dir/fold-character.cpp.o] Error 1
gmake[1]: *** [CMakeFiles/Makefile2:144317: tools/flang/lib/Evaluate/CMakeFiles/FortranEvaluate.dir/all] Error 2
gmake: *** [Makefile:156: all] Error 2
```