[lldb/test] Update test/API/functionalities/load_lazy to macOS 12

In macOS 12, dyld switched to using chained fixups. As a result, all symbols
are bound at launch and there are no lazy pointers any more. Since we wish to
import/dlopen() a dylib with missing symbols, we need to use a weak import.
This applies to all macOS 12-aligned OS releases, e.g. iOS 15, etc.

rdar://81295101

Differential Revision: https://reviews.llvm.org/D112034