Ask for debug output

Author: neonichu

Sources/Commands/Utilities/TestingSupport.swift

@@ -136,6 +136,7 @@ enum TestingSupport {
         #elseif os(Linux)
         // Pass this explicitly on Linux because XCTest started requiring it, rdar://103054033
         env["LD_LIBRARY_PATH"] = "/usr/lib/swift/linux"
+        env["LD_DEBUG"] = "all"
         #endif
         return env
         #else