Leak fewer symbols

[jrcheli]

Right now, I was surprised at how many symbols "nm -D libscope.so" reports as being " T ". Some of these should not be exported.

Invert the way we're doing libscope.map, to list symbols we want exported, instead of listing all the ones we don't????

[michalbiesek]

With work on #1057 We can distinguish EXPORTOFF in wrap.c for the two functions categories:

• one which we intent to interpose
• the second we do not intend to get interposed e.g. https://github.com/criblio/appscope/blob/3fa9603bbe3f27f49b539568d4ef47580da5141d/src/wrap.c#L4225-L4228