Work around a bug in the interaction between newer dyld's and older simulator dyld's

[jimingham]

There's a bad interaction between the macOS 14 dyld and the "dyld_sim" shim that comes from older (iOS 15) simulator downloads that results in dyld reporting some modules twice in the return from the dyld callback to list modules. The records were identical, but lldb wasn't happy with seeing the duplicates...

Since it's not possible to load two different modules at the same address, this change just picks the first instance of any entries that have the same load address.

There really isn't a good way to test this patch.

(cherry picked from commit 32dd5b20973bde1ef77fa3b84b9f85788a1a303a)

[jimingham]

@swift-ci please test