SwiftCompilerSources: add StoreBorrowInst and BorrowIntroducingInstruction

`BorrowIntroducingInstruction` is a protocol to which all instructions conform which start a borrow-scope which must be ended by `EndBorrowInst` instructions: `begin_borrow`, `load_borrow` and `store_borrow`

SwiftCompilerSources/Sources/SIL/Registration.swift

@@ -41,6 +41,7 @@ public func registerSILClasses() {
   register(StoreInst.self)
   register(StoreWeakInst.self)
   register(StoreUnownedInst.self)
+  register(StoreBorrowInst.self)
   register(AssignInst.self)
   register(CopyAddrInst.self)
   register(EndAccessInst.self)