Fix deletion in testsuite

Author: jishnub

test/runtests.jl

@@ -10,7 +10,7 @@ end
 testsuite = find_tests(pwd())
 
 if "--downstream_integration_test" in ARGS
-    delete!(testsuite, "test_aqua.jl")
+    delete!(testsuite, "test_aqua")
 end
 
 filtered_args = filter(!=("--downstream_integration_test"), ARGS)