Add Testing frameworks for macOS platforms

[sebastianv1]

When upgrading to Xcode 26.5 we discovered that SwiftSyntaxMacrosTestSupport was missing from the prebuilt BUILD.bazel file.

It looks like it was removed as a part of the linux distribution support; but it still might make sense to include it for at least non-linux targets?

When generating the BUILD.bazel with and without my changes here was the resulting diff:

+swift_import(
+    name = "SwiftSyntaxMacrosGenericTestSupport",
+    module_name = "SwiftSyntaxMacrosGenericTestSupport",
+    archives = select({
+        "@platforms//os:macos": ["macos-arm64/libSwiftSyntaxMacrosGenericTestSupport.a"],
+    }),
+    swiftdoc = select({
+        "@platforms//os:macos": "macos-arm64/SwiftSyntaxMacrosGenericTestSupport.swiftdoc",
+    }),
+    swiftinterface = select({
+        "@platforms//os:macos": "macos-arm64/SwiftSyntaxMacrosGenericTestSupport.swiftinterface",
+    }),
+    deps = [":SwiftDiagnostics", ":SwiftIDEUtils", ":SwiftParser", ":SwiftSyntaxMacroExpansion", ":SwiftSyntaxMacros", ":_SwiftSyntaxGenericTestSupport"],
+    visibility = ["//visibility:public"],
+)
+
+alias(
+    name = "SwiftSyntaxMacrosGenericTestSupport_opt",
+    actual = ":SwiftSyntaxMacrosGenericTestSupport",
+    visibility = ["//visibility:public"],
+)
+
+swift_import(
+    name = "SwiftSyntaxMacrosTestSupport",
+    module_name = "SwiftSyntaxMacrosTestSupport",
+    archives = select({
+        "@platforms//os:macos": ["macos-arm64/libSwiftSyntaxMacrosTestSupport.a"],
+    }),
+    swiftdoc = select({
+        "@platforms//os:macos": "macos-arm64/SwiftSyntaxMacrosTestSupport.swiftdoc",
+    }),
+    swiftinterface = select({
+        "@platforms//os:macos": "macos-arm64/SwiftSyntaxMacrosTestSupport.swiftinterface",
+    }),
+    deps = [":SwiftSyntax", ":SwiftSyntaxMacroExpansion", ":SwiftSyntaxMacros", ":SwiftSyntaxMacrosGenericTestSupport"],
+    visibility = ["//visibility:public"],
+)
+
+alias(
+    name = "SwiftSyntaxMacrosTestSupport_opt",
+    actual = ":SwiftSyntaxMacrosTestSupport",
+    visibility = ["//visibility:public"],
+)
+
 swift_import(
     name = "SwiftSyntaxMacros",
     module_name = "SwiftSyntaxMacros",
@@ -548,6 +592,49 @@ alias(
     visibility = ["//visibility:public"],
 )

+swift_import(
+    name = "_SwiftSyntaxGenericTestSupport",
+    module_name = "_SwiftSyntaxGenericTestSupport",
+    archives = select({
+        "@platforms//os:macos": ["macos-arm64/lib_SwiftSyntaxGenericTestSupport.a"],
+    }),
+    swiftdoc = select({
+        "@platforms//os:macos": "macos-arm64/_SwiftSyntaxGenericTestSupport.swiftdoc",
+    }),
+    swiftinterface = select({
+        "@platforms//os:macos": "macos-arm64/_SwiftSyntaxGenericTestSupport.swiftinterface",
+    }),
+    visibility = ["//visibility:public"],
+)
+
+alias(
+    name = "_SwiftSyntaxGenericTestSupport_opt",
+    actual = ":_SwiftSyntaxGenericTestSupport",
+    visibility = ["//visibility:public"],
+)
+
+swift_import(
+    name = "_SwiftSyntaxTestSupport",
+    module_name = "_SwiftSyntaxTestSupport",
+    archives = select({
+        "@platforms//os:macos": ["macos-arm64/lib_SwiftSyntaxTestSupport.a"],
+    }),
+    swiftdoc = select({
+        "@platforms//os:macos": "macos-arm64/_SwiftSyntaxTestSupport.swiftdoc",
+    }),
+    swiftinterface = select({
+        "@platforms//os:macos": "macos-arm64/_SwiftSyntaxTestSupport.swiftinterface",
+    }),
+    deps = [":SwiftBasicFormat", ":SwiftSyntax", ":SwiftSyntaxBuilder", ":SwiftSyntaxMacroExpansion", ":_SwiftSyntaxGenericTestSupport"],
+    visibility = ["//visibility:public"],
+)
+
+alias(
+    name = "_SwiftSyntaxTestSupport_opt",
+    actual = ":_SwiftSyntaxTestSupport",
+    visibility = ["//visibility:public"],
+)
+