no hardwired timeout in Isabelle distribution (unlike on AFP): reverting part of 74c75da4cb01 -- without further tinkering it breaks isabelle_cronjob builds;

--- a/src/HOL/ROOT	Fri Aug 04 19:17:49 2023 +0200
+++ b/src/HOL/ROOT	Sun Aug 06 14:48:25 2023 +0200
@@ -98,7 +98,7 @@
   document_files "root.bib" "root.tex"
 
 session "HOL-Analysis" (main timing) in Analysis = HOL +
-  options [timeout=1800, document_tags = "theorem%important,corollary%important,proposition%important,class%important,instantiation%important,subsubsection%unimportant,%unimportant",
+  options [document_tags = "theorem%important,corollary%important,proposition%important,class%important,instantiation%important,subsubsection%unimportant,%unimportant",
     document_variants = "document:manual=-proof,-ML,-unimportant"]
   sessions
     "HOL-Library"
@@ -111,7 +111,7 @@
     "root.bib"
 
 session "HOL-Complex_Analysis" (main timing) in Complex_Analysis = "HOL-Analysis" +
-  options [timeout=300, document_tags = "theorem%important,corollary%important,proposition%important,class%important,instantiation%important,subsubsection%unimportant,%unimportant",
+  options [document_tags = "theorem%important,corollary%important,proposition%important,class%important,instantiation%important,subsubsection%unimportant,%unimportant",
     document_variants = "document:manual=-proof,-ML,-unimportant"]
   theories
     Complex_Analysis
@@ -125,7 +125,7 @@
     Metric_Arith_Examples
 
 session "HOL-Homology" (timing) in Homology = "HOL-Analysis" +
-  options [timeout=300, document_tags = "theorem%important,corollary%important,proposition%important,class%important,instantiation%important,subsubsection%unimportant,%unimportant",
+  options [document_tags = "theorem%important,corollary%important,proposition%important,class%important,instantiation%important,subsubsection%unimportant,%unimportant",
     document_variants = "document:manual=-proof,-ML,-unimportant"]
   sessions
     "HOL-Algebra"
@@ -322,7 +322,6 @@
     Fundamental Theorem of Arithmetic, Chinese Remainder Theorem, Fermat/Euler
     Theorem, Wilson's Theorem, some lemmas for Quadratic Reciprocity.
   "
-  options [timeout = 300]
   sessions
     "HOL-Algebra"
   theories
@@ -847,7 +846,6 @@
     ATP_Problem_Import
 
 session "HOL-Probability" (main timing) in "Probability" = "HOL-Analysis" +
-  options [timeout = 600]
   sessions
     "HOL-Combinatorics"
   theories