Removed useless manipulation of std::move'd value

This attempt to retain a std::move'd value was inadvertently left in
place in a previous CL. It's harmless, but should have been removed.

Change-Id: I485e0f14d921fe6c87a62520c7478a28e8ce28d8
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/358517
Auto-Submit: Ethan Nicholas <ethannicholas@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>

src/sksl/SkSLIRGenerator.cpp

@@ -1408,7 +1408,6 @@ void IRGenerator::convertEnum(const ASTNode& e) {
                                                             /*arraySize=*/0, std::move(value));
         var->setDeclaration(declaration.get());
         fSymbolTable->add(std::move(var));
-        fSymbolTable->takeOwnershipOfIRNode(std::move(value));
         fSymbolTable->takeOwnershipOfIRNode(std::move(declaration));
     }
     // Now we orphanize the Enum's symbol table, so that future lookups in it are strict