Add override to C++ code generation for InternalGetTable
Add override to C++ code generation for InternalGetTable

This should conclude the larger efforts from issue #8612
regarding clang warnings.

google/protobuf,google/protobuf,google/protobuf,google/protobuf,google/protobuf,google/protobuf,google/protobuf,google/protobuf,google/protobuf,google/protobuf,google/protobuf