[flang] Fix linker error for debug builds. (#83250)

PR #81833 introduced some changes to broke some debug builds. This
happened due to an indirectly included file referencing an `operator <<`
function which is defined in a `.cpp` file that not linked with `tco`
and `fir-opt`.

Author: ergawy

flang/include/flang/Lower/AbstractConverter.h

@@ -16,7 +16,6 @@
 #include "flang/Common/Fortran.h"
 #include "flang/Lower/LoweringOptions.h"
 #include "flang/Lower/PFTDefs.h"
-#include "flang/Lower/SymbolMap.h"
 #include "flang/Optimizer/Builder/BoxValue.h"
 #include "flang/Semantics/symbol.h"
 #include "mlir/IR/Builders.h"
@@ -54,6 +53,7 @@ class DerivedTypeSpec;
 
 namespace lower {
 class SymMap;
+class SymbolBox;
 namespace pft {
 struct Variable;
 }

flang/lib/Lower/OpenMP/DataSharingProcessor.cpp

@@ -14,6 +14,7 @@
 
 #include "Utils.h"
 #include "flang/Lower/PFTBuilder.h"
+#include "flang/Lower/SymbolMap.h"
 #include "flang/Optimizer/Builder/Todo.h"
 #include "flang/Semantics/tools.h"
 #include "mlir/Dialect/OpenMP/OpenMPDialect.h"