[fix] Better SQL SELECT instead of a timeout query

This query runs when filtering by files or components with "anywhere
on bugpath" option. In this case the following query was generated:

SELECT <columns> FROM reports WHERE reports.id IN (id1, id2, ...);

The ID list at "IN" block can be so huges that it eats up all the memory
and times out the query. This ID list is now replaced with a nested
select:

SELECT <columns> FROM reports WHERE reports.id IN
  (SELECT report_id FROM <some tables>);

web/server/codechecker_server/api/report_server.py

@@ -534,39 +534,31 @@ def get_source_component_file_query(
 
 def get_reports_by_bugpath_filter(session, file_filter_q) -> Set[int]:
     """
-    This function returns a set of report IDs that are related to any file
+    This function returns a query for report IDs that are related to any file
     described by the query in the second parameter, either because their bug
     path goes through these files, or there is any bug note, etc. in these
     files.
     """
-    def first_col_values(query):
-        """
-        This function executes a query and returns the set of first columns'
-        values.
-        """
-        return set(map(lambda x: x[0], query.all()))
-
-    report_ids = set()
-
-    q = session.query(Report.id) \
+    q_report = session.query(Report.id) \
         .join(File, File.id == Report.file_id) \
         .filter(file_filter_q)
 
-    report_ids.update(first_col_values(q))
-
-    q = session.query(BugPathEvent.report_id) \
+    q_bugpathevent = session.query(BugPathEvent.report_id) \
         .join(File, File.id == BugPathEvent.file_id) \
         .filter(file_filter_q)
 
-    report_ids.update(first_col_values(q))
+    q_bugreportpoint = session.query(BugReportPoint.report_id) \
+        .join(File, File.id == BugReportPoint.file_id) \
+        .filter(file_filter_q)
 
-    q = session.query(ExtendedReportData.report_id) \
+    q_extendedreportdata = session.query(ExtendedReportData.report_id) \
         .join(File, File.id == ExtendedReportData.file_id) \
         .filter(file_filter_q)
 
-    report_ids.update(first_col_values(q))
-
-    return report_ids
+    return q_report.union(
+        q_bugpathevent,
+        q_extendedreportdata,
+        q_bugreportpoint)
 
 
 def get_reports_by_components(session, component_names: List[str]) -> Set[int]: