sage.doctest.control: Do not fail if sage.libs.arb cannot be imported

[mkoeppe]

(extracted from #29865)

The dependency on sage.libs.arb was introduced in #30486.
We catch ImportError so that there are no failures in modularized
settings (#29865 - packages sagemath-objects, sagemath-categories).

CC: @kiwifb @dimpase @tobiasdiez

Component: refactoring

Author: Matthias Koeppe

Branch/Commit: 8e57f63

Reviewer: François Bissey

Issue created by migration from https://trac.sagemath.org/ticket/31334

[mkoeppe]

Branch: u/mkoeppe/sage_doctest_control__do_not_fail_if_sage_libs_arb_cannot_be_imported

[mkoeppe]

Commit: 8e57f63

[mkoeppe]

New commits:

8e57f63

src/sage/doctest/control.py: Do not fail if sage.libs.arb cannot be imported

[kiwifb]

comment:3

This is trivially safe.

[kiwifb]

Reviewer: François Bissey

[mkoeppe]

comment:4

Thanks!

[vbraun]

Changed branch from u/mkoeppe/sage_doctest_control__do_not_fail_if_sage_libs_arb_cannot_be_imported to 8e57f63