[Tests] add unit coverage for nvm_version_greater_than_or_equal_to

Author: Shrikant

test/fast/Unit tests/nvm_version_greater_than_or_equal_to

@@ -15,6 +15,14 @@ if nvm_version_greater_than_or_equal_to 0.10.0 0.20.12; then
   die '"nvm_version_greater_than_or_equal_to 0.10.0 0.20.12" returned true'
 fi
 
+if nvm_version_greater_than_or_equal_to 0.2.12 0.10.0; then
+  die '"nvm_version_greater_than_or_equal_to 0.2.12 0.10.0" returned true'
+fi
+
 if nvm_version_greater_than_or_equal_to 0.10.0 ''; then
   die '"nvm_version_greater_than_or_equal_to" returned true with an empty argument'
 fi
+
+if nvm_version_greater_than_or_equal_to '' 0.10.0; then
+  die '"nvm_version_greater_than_or_equal_to" returned true with an empty first argument'
+fi