reduced padding in some classes/structs

[firewave]

Based on reviewing -Wpadded warnings in frequently used classes/structs. There's also some potential candidates in simplecpp.

If wanted to can try to provide sizeof() before and after.

I did a valgrind --tool=massif run on mame_regtest and it showed a small difference in the memory usage of Token.

Before:
2.3312988281 MiB: Token (lib/token.cpp:57)

After:
2.2017822266 MiB: Token (lib/token.cpp:57)

I did not profile this with callgrind (yet).

[firewave]

It also improves overall performance a bit. Scanning mame_regtest with DISABLE_VALUEFLOW=1 and --enable=all --inconclusive gives the following:

Clang 13 2,469,746,867 -> 2,458,134,208

But it caused a small visible regression in VariableMap::addVariable(std::__cxx11::basic_string<> const&, bool) with void std::vector<>::_M_realloc_insert<>(__gnu_cxx::__normal_iterator<>, std::pair<>&&) (cppcheck: vector.tcc, ...) from 688 to 1029 per call in average.

[firewave]

At least the following boundary alignment padding was saved:
Function - 4 bytes
TokenImpl - 4 bytes
ValueFlow::Value - 0 bytes
LifetimeToken - 1 byte