IntegrationTestSpec should not ignore leading/trailing whitespace by default

[droazen]

IntegrationTestSpec currently ignores leading/trailing whitespace by default when doing its comparison against expected outputs. This is problematic given that whitespace can include things like field delimiters, leading to bugs like the one fixed in #7559

We should change the default to not ignore leading/trailing whitespace. Tests that have a legitimate reason for ignoring it can then explicitly opt-in by calling setTrimWhiteSpace()