debugging on the CI host

Author: compnerd

test/ModuleInterface/swift_build_sdk_interfaces/check-only-mode.swift

@@ -12,7 +12,7 @@
 // CHECK-DAG: Flat.swiftmodule
 // CHECK-DAG: FMWK.swiftmodule
 
-// RUN: %target-typecheck-verify-swift -sdk %t/sdk -Fsystem %t/sdk/System/Library/Frameworks -I %t/sdk/usr/lib/swift/ -module-cache-path %t/MCP -prebuilt-module-cache-path %t/prebuilt
+// RUN: %target-typecheck-verify-swift -sdk %t/sdk -Fsystem %t/sdk/System/Library/Frameworks -I %t/sdk/usr/lib/swift/ -module-cache-path %t/MCP -prebuilt-module-cache-path %t/prebuilt -Xllvm -debug
 // RUN: %{python} %S/../ModuleCache/Inputs/check-is-forwarding-module.py %t/MCP/*.swiftmodule
 
 // Touch a file in the SDK (to make it look like it changed) and try again.