[libc++abi] Make the error message for recursive initialization of...

[libc++abi] Make the error message for recursive initialization of function-local statics more explicit

The new message is a bit verbose, but it makes it clearer that this isn't
a problem in libc++abi, but instead a problem in the user's code. Otherwise,
we get bugs sent down to libc++abi because people see this message in their
crash logs.

Differential Revision: https://reviews.llvm.org/D148630