Kotlin: Fix integration tests on Mac

Author: igfoo

java/ql/integration-tests/posix-only/kotlin/external-property-overloads/test.py

@@ -1,4 +1,5 @@
 from create_database_utils import *
 
+os.mkdir('lib')
 runSuccessfully(["kotlinc", "test.kt", "-d", "lib"])
 run_codeql_database_create(["kotlinc user.kt -cp lib"], lang="java")

java/ql/integration-tests/posix-only/kotlin/java-interface-redeclares-tostring/test.py

@@ -1,4 +1,5 @@
 from create_database_utils import *
 
+os.mkdir('bin')
 runSuccessfully(["javac", "Test.java", "-d", "bin"])
 run_codeql_database_create(["kotlinc user.kt -cp bin"], lang="java")