[Driver] Correctly handle static C++ standard library
When statically linking C++ standard library, we shouldn't add -Bdynamic
after including the library on the link line because that might override
user settings like -static and -static-pie. Rather, we should surround
the library with --push-state/--pop-state to make sure that -Bstatic
only applies to C++ standard library and nothing else. This has been
supported since GNU ld 2.25 (2014) so backwards compatibility should
no longer be a concern.
Differential Revision: https://reviews.llvm.org/D110128