[flang] Remove unused code and redundant assertion.

[PeteSteinfeld]

All builds and tests correctly and looks good.

flang/include/flang/Lower/Bridge.h

return LoweringBridge(ctx, defaultKinds, intrinsics, allCooked, triple,
                           kindMap);
   }
 
   //===--------------------------------------------------------------------===//
   // Getters
   //===--------------------------------------------------------------------===//
 
   mlir::MLIRContext &getMLIRContext() { return context; }
-  mlir::ModuleOp &getModule() {
-    assert(module && "This bridge is missing an MLIR module");
-    return *module.get();
-  }
+
+  /// Get the ModuleOp. It can never be null, which is asserted in the ctor.
+  mlir::ModuleOp &getModule() { return *module.get(); }
+
   const Fortran::common::IntrinsicTypeDefaultKinds &getDefaultKinds() const {
     return defaultKinds;
   }
   const Fortran::evaluate::IntrinsicProcTable &getIntrinsicTable() const {
     return intrinsics;
   }
   const Fortran::parser::AllCookedSources *getCookedSource() const {
     return cooked;
   }
 
   /// Get the kind map.
   const fir::KindMapping &getKindMap() const { return kindMap; }
 
   /// Create a folding context. Careful: this is very expensive.
   Fortran::evaluate::FoldingContext createFoldingContext() const;
 
-  bool validModule() { return (module != nullptr); }
-
   //===--------------------------------------------------------------------===//
   // Perform the creation of an mlir::ModuleOp
   //===--------------------------------------------------------------------===//
 
   /// Read in an MLIR input file rather than lowering Fortran sources.
   /// This is intended to be used for testing.
   void parseSourceFile(llvm::SourceMgr &);
 

flang/lib/Lower/Bridge.cpp

context.getDiagEngine().registerHandler([](mlir::Diagnostic &diag) {
     os.flush();
     return mlir::success();
   });
 
   // Create the module and attach the attributes.
   module = std::make_unique<mlir::ModuleOp>(
       mlir::ModuleOp::create(mlir::UnknownLoc::get(&context)));
   assert(module.get() && "module was not created");
-  fir::setTargetTriple(*module.get(), triple);
-  fir::setKindMapping(*module.get(), kindMap);
+  fir::setTargetTriple(getModule(), triple);
+  fir::setKindMapping(getModule(), kindMap);
 }