sagemathgh-40998: Miscellaneous "long time" additions
    
Fix a few random warnings I picked out of the CI, all confirmed locally.
    
URL: sagemath#40998
Reported by: Michael Orlitzky
Reviewer(s): David Coudert

Author: Release Manager

src/sage/combinat/tiling.py

@@ -1450,6 +1450,7 @@ def self_surrounding(self, radius, remove_incomplete_copies=True,
 
         ::
 
+            sage: # long time
             sage: solution = H.self_surrounding(8, remove_incomplete_copies=False)
             sage: G = sum([p.show2d() for p in solution], Graphics())                   # needs sage.plot
         """

src/sage/geometry/hyperplane_arrangement/ordered_arrangement.py

@@ -494,7 +494,7 @@ def projective_meridians(self):
              1: [x3], 2: [x4], 3: [x1], 4: [x2], 5: [x0]}
             sage: A4.<t1, t2, t3, t4> = OrderedHyperplaneArrangements(QQ)
             sage: H = A4(hyperplane_arrangements.braid(4))
-            sage: H.projective_meridians()
+            sage: H.projective_meridians()  # long time
             {0: [x2^-1*x0^-1*x4^-1*x3^-1*x1^-1], 1: [x3],
              2: [x4], 3: [x0], 4: [x2], 5: [x1]}
 

src/sage/rings/polynomial/multi_polynomial_libsingular.pyx

@@ -4747,6 +4747,7 @@ cdef class MPolynomial_libsingular(MPolynomial_libsingular_base):
 
         Ensure interrupt does not make the internal state inconsistent::
 
+            sage: # long time
             sage: R.<x,y> = QQ[]
             sage: n = 17  # chosen so that the computation takes > 1 second but not excessively long.
             ....: # when Singular improves the algorithm or hardware gets faster, increase n.

src/sage/schemes/elliptic_curves/isogeny_class.py

@@ -1406,8 +1406,9 @@ def possible_isogeny_degrees(E, algorithm='Billerey', max_l=None,
 
     Over an extension field::
 
+        sage: # long time
         sage: E3 = E.change_ring(CyclotomicField(3))
-        sage: possible_isogeny_degrees(E3)                                              # long time (5s)
+        sage: possible_isogeny_degrees(E3)
         [5]
         sage: [phi.degree() for phi in E3.isogenies_prime_degree()]
         [5, 5]

src/sage/tests/book_schilling_zabrocki_kschur_primer.py

@@ -786,6 +786,7 @@
 
 Sage example in ./kschurnotes/notes-mike-anne.tex, line 5588::
 
+sage: # long time
 sage: SymQ3 = Sym.kBoundedQuotient(3,t=1)
 sage: G1 = SymQ3.AffineGrothendieckPolynomial([1],6)
 sage: G2 = SymQ3.AffineGrothendieckPolynomial([2],6)