[issue31847] Fix commented out tests in test_syntax

[Serhiy Storchaka]

New submission from Serhiy Storchaka <storchaka+cpython at gmail.com>:

Two doctest tests in test_syntax are commented out because SyntaxWarning was expected, but doctests couldn't be used for testing them.

But now SyntaxError is raised in these cases instead of SyntaxWarning.

The proposed PR restores and fixes tests.

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assignee: serhiy.storchaka
components: Tests
messages: 304800
nosy: serhiy.storchaka
priority: normal
severity: normal
stage: patch review
status: open
title: Fix commented out tests in test_syntax
type: enhancement
versions: Python 3.6, Python 3.7

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue31847>
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