build 5.9 SDKs to match earliest version which runs in CI

Author: euanh

Tests/SwiftSDKGeneratorTests/EndToEndTests.swift

@@ -323,12 +323,10 @@ final class Swift59_UbuntuEndToEndTests: XCTestCase {
   }
 
   func testAarch64FromContainer() async throws {
-    try skipSlow()
     try await buildTestcases(config: config.withArchitecture("aarch64").withDocker())
   }
 
   func testX86_64FromContainer() async throws {
-    try skipSlow()
     try await buildTestcases(config: config.withArchitecture("x86_64").withDocker())
   }
 }
@@ -381,10 +379,12 @@ final class Swift60_UbuntuEndToEndTests: XCTestCase {
   }
 
   func testAarch64FromContainer() async throws {
+    try skipSlow()
     try await buildTestcases(config: config.withArchitecture("aarch64").withDocker())
   }
 
   func testX86_64FromContainer() async throws {
+    try skipSlow()
     try await buildTestcases(config: config.withArchitecture("x86_64").withDocker())
   }
 }