[Autolink Extract] Filter out StringProcessing library from being linked more than once.

We cannot filter all libraries because duplicate -l flags have a semantic meaning based on their order, but filtering out just the common Swift libraries should yield a good size improvement already and is safe.

Author: artemcm

lib/DriverTool/autolink_extract_main.cpp

@@ -249,6 +249,7 @@ int autolink_extract_main(ArrayRef<const char *> Args, const char *Argv0,
       {"-lswiftSwiftOnoneSupport", false},
       {"-lswiftCore", false},
       {"-lswift_Concurrency", false},
+      {"-lswift_StringProcessing", false},
   };
 
   // Extract the linker flags from the objects.

test/AutolinkExtract/import.swift

@@ -9,6 +9,7 @@
 // REQUIRES: autolink-extract
 
 // UNIQUE-COUNT-1: -lswiftCore
+// UNIQUE-COUNT-1: -lswift_StringProcessing
 
 // CHECK-elf-DAG: -lswiftCore
 // CHECK-elf-DAG: -lempty