[libcxx] [test] D27268: Fix MSVC x64 warning C4267 "conversion from 'size_t'...

[libcxx] [test] D27268: Fix MSVC x64 warning C4267 "conversion from 'size_t' to 'int' [or 'unsigned int'], possible loss of data", part 2/4.

Use static_cast<int> when storing size_t in int (or passing size_t to int).

Also, remove a spurious semicolon in test/support/archetypes.hpp.

test/support/count_new.hpp
Additionally, change data members (and parameters) to size_t.

llvm-svn: 288752