Bug 991466 - remove the specCompliant flag from CSP since it's no longer needed. (r=ckerschb,jst)

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extra : rebase_source : 754264fd1721946a78c461e08d210bb5a1fdbda4
Bug 991466 - Remove pushprevenv for security.csp.speccompliant from tests since the pref no longer has effect. (r=ckerschb)

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extra : rebase_source : 61a52591fc5616486900367e7c06729cce889f13