When CLI contains unsupported parameters, the `context.options` may be null, that is violated by `populateUserProperties` method.

Before (master):
```
$ mvn --encrypt-master-password xxxxx
[ERROR] Error executing Maven.
[ERROR] Error parsing program arguments
[ERROR] Caused by: Failed to parse CLI arguments: Unrecognized option: --encrypt-master-password
[ERROR] Error populating user properties
[ERROR] Caused by: Cannot invoke "org.apache.maven.api.cli.Options.userProperties()" because "context.options" is null
[ERROR] Error reading core extensions descriptor
[ERROR] Caused by: null
$
```

With PR:
```
$ mvn --encrypt-master-password 
[ERROR] Error executing Maven.
[ERROR] Error parsing program arguments
[ERROR] Caused by: Failed to parse CLI arguments: Unrecognized option: --encrypt-master-password
$
```