Merge pull request #1382 from swiftwasm/maxd/5.3-forks

Use SwiftWasm forks of Foundation/XCTest in 5.3 branch

Author: MaxDesiatov

utils/update_checkout/update-checkout-config.json

@@ -17,9 +17,9 @@
         "swift-stress-tester": {
             "remote": { "id": "apple/swift-stress-tester" } },
         "swift-corelibs-xctest": {
-            "remote": { "id": "apple/swift-corelibs-xctest" } },
+            "remote": { "id": "swiftwasm/swift-corelibs-xctest" } },
         "swift-corelibs-foundation": {
-            "remote": { "id": "apple/swift-corelibs-foundation" } },
+            "remote": { "id": "swiftwasm/swift-corelibs-foundation" } },
         "swift-corelibs-libdispatch": {
             "remote": { "id": "apple/swift-corelibs-libdispatch" } },
         "swift-integration-tests": {