Don't reduce test timeout to less than default

This removes all overrides of TIMEOUT that are less than or equal to the
default timeout.

stdlib/tst-empty-env.c

@@ -53,6 +53,5 @@ do_test (int argc, char **argv)
   return 1;
 }
 
-#define TIMEOUT 3
 #define TEST_FUNCTION_ARGV do_test
 #include <support/test-driver.c>