scripted-diff: Make use of the improved handling of two consecutive right angle brackets in C++11 #10597

Improve code readability by removing the legacy handling of two consecutive
right angle brackets that was required prior to C++11. Non-functional change.

After this commit:

```
$ git grep "> >" -- "*.cpp" "*.h" | grep -v '/leveldb/' | wc -l
0
```

-BEGIN VERIFY SCRIPT-
sed -i 's/> >/>>/g' src/*.cpp src/*.h src/compat/*.cpp src/policy/*.cpp src/qt/*.cpp src/qt/*.h src/qt/test/*.cpp src/rpc/*.cpp src/script/*.cpp src/script/*.h src/support/allocators/*.h src/test/*.cpp src/wallet/*.cpp src/wallet/*.h
sed -i 's/> >/>>/g' src/keystore.h
sed -i 's/std::vector< std::vector/std::vector<std::vector/g' src/qt/rpcconsole.cpp
sed -i 's/std::set< std::set/std::set<std::set/g' src/wallet/wallet.cpp src/wallet/wallet.h
sed -i 's/>\* >/>*>/g' src/wallet/wallet.cpp
sed -i 's/std::map< CTxDestination/std::map<CTxDestination/g' src/wallet/wallet.cpp
-END VERIFY SCRIPT-