fix missing %import-libdispatch in test

Author: ktoso

test/Concurrency/Runtime/custom_executors_complex_equality_crash.swift

@@ -1,7 +1,7 @@
 // NOT: %target-run-simple-swift( -Xfrontend -disable-availability-checking %import-libdispatch -parse-as-library)
 
 // RUN: %empty-directory(%t)
-// RUN: %target-build-swift -Xfrontend -disable-availability-checking -parse-as-library %s -o %t/a.out
+// RUN: %target-build-swift -Xfrontend -disable-availability-checking %import-libdispatch -parse-as-library %s -o %t/a.out
 // RUN: %target-codesign %t/a.out
 // RUN: %env-SWIFT_IS_CURRENT_EXECUTOR_LEGACY_MODE_OVERRIDE=legacy %target-run %import-libdispatch %t/a.out
 // RUN: %env-SWIFT_IS_CURRENT_EXECUTOR_LEGACY_MODE_OVERRIDE=swift6 %target-run %import-libdispatch %t/a.out