Fix #655: Test Env map make mutable

[melloware]

Fix #655: All maps mutable

[ia3andy]

@melloware this is not what I meant, Immutable Map are ok, we just need to make sure we don't mutate map from we don't know the origin. So whenever a put is made from a Map created elsewhere, we need to create a new Map from it.

[melloware]

@ia3andy i figured it was better to be safe then sorry. But yeah to me it looks like its only one line as testenv comes from a Config property.

PR updated

[melloware]

Test env comes from here

    @ConfigDocDefault("CI=true")
    Map<String, String> testEnv();

so it must be an immutable map being passed from Config

[ia3andy]

LGTM