Shift issue numbers for patterns in #8286

- [ ] The rest of:
```
$ grep -R 'bug[[:space:]]*[#]\?[0-9]\+' [^.]*|fgrep -v '/spin.ipynb:'
sympy/core/tests/test_equal.py:def test_cmp_bug1():
sympy/core/tests/test_equal.py:def test_cmp_bug2():
sympy/core/tests/test_match.py:def test_derivative_bug1():
sympy/core/tests/test_match.py:def test_match_deriv_bug1():
sympy/core/tests/test_match.py:def test_match_bug2():
sympy/core/tests/test_match.py:def test_match_bug3():
sympy/core/tests/test_match.py:def test_match_bug4():
sympy/core/tests/test_match.py:def test_match_bug5():
sympy/core/tests/test_match.py:def test_match_bug6():
sympy/core/tests/test_match.py:def test_Derivative_bug1():
sympy/core/tests/test_subs.py:def test_subbug1():
sympy/core/tests/test_subs.py:def test_subbug2():
sympy/core/tests/test_subs.py:def test_deriv_sub_bug3():
sympy/core/tests/test_arit.py:def test_bug1():
sympy/core/tests/test_arit.py:def test_bug3():
sympy/core/tests/test_function.py:def test_bug1():
sympy/series/tests/test_nseries.py:def test_seriesbug1():
sympy/series/tests/test_nseries.py:def test_bug2():  # 1/log(0) * log(0) problem
sympy/series/tests/test_nseries.py:def test_bug3():
sympy/series/tests/test_nseries.py:def test_seriesbug2():
sympy/series/tests/test_nseries.py:def test_seriesbug2b():
sympy/series/tests/test_nseries.py:def test_seriesbug2d():
sympy/series/tests/test_nseries.py:def test_seriesbug2c():
sympy/series/tests/test_nseries.py:def test_expbug4():
sympy/series/tests/test_nseries.py:def test_logbug4():
sympy/series/tests/test_nseries.py:def test_expbug5():
sympy/series/tests/test_nseries.py:def test_bug4():
sympy/series/tests/test_nseries.py:def test_bug5():
```