[SwiftCompilerSources] Add swift_get_access_base unit tests.

Add a unit test harness to SwiftCompilerSources to match the one in C++ since
both source bases have different implementations of the same utilities, and they
must be consistent for correctness.

SwiftCompilerSources/Sources/Optimizer/Utilities/AccessUtilsTest.swift

@@ -0,0 +1,23 @@
+//===--- AccessUtils.swift - Utilities for analyzing memory accesses ------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2024 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+//
+// TODO: Move this to AccessUtils.swift when FunctionTest is available.
+//
+//===----------------------------------------------------------------------===//
+
+let getAccessBaseTest = FunctionTest("swift_get_access_base") {
+  function, arguments, context in
+  let address = arguments.takeValue()
+  print("Address: \(address)")
+  let base = address.accessBase
+  print("Base: \(base)")
+}