Fix bad negation in functions

Author: JonRowe

script/run_build

@@ -31,7 +31,7 @@ fi
 if is_mri; then
   # As of 2019-09-24 this causes a huge log due to a cicular dependency
   # disable for now
-  if !is_mri_193; then
+  if [ ! is_mri_193 ]; then
     fold "one-by-one specs" run_specs_one_by_one
   fi
   run_all_spec_suites