Associate loaded breakpoints with a moving cursor

Loaded breakpoints don't trigger markChanged(), which is normally
responsible for getting a moving cursor for breakpoints. Instead the moving
cursor for loaded breakpoints is now added in textDocumentCreated().
Logic for adding moving cursors is also moved into seperate function, as
the same code snippet was used multiple times.

This fixes bug 424431.
1 job for !146 with fix_breakpoints in 60 minutes (queued for 14 minutes and 29 seconds)
Status Job ID Name Coverage
failed #57984
linux kf5-qt5 qt5.12


Name Stage Failure
linux kf5-qt5 qt5.12 Build The script exceeded the maximum execution time set for the job
[ 85%] Building CXX object kdevplatform/language/codegen/tests/CMakeFiles/test_templatesmodel.dir/test_templatesmodel.cpp.o
[ 85%] Linking CXX executable test_templatesmodel
[ 85%] Built target test_templatesmodel
Scanning dependencies of target test_templateclassgenerator
[ 85%] Building CXX object kdevplatform/language/codegen/tests/CMakeFiles/test_templateclassgenerator.dir/test_templateclassgenerator_autogen/mocs_compilation.cpp.o
[ 85%] Building CXX object kdevplatform/language/codegen/tests/CMakeFiles/test_templateclassgenerator.dir/test_templateclassgenerator.cpp.o
Uploading artifacts for failed job
Pulling docker image gitlab/gitlab-runner-helper:x86_64-6fbc7474 ...
ERROR: Job failed: execution took longer than 1h0m0s seconds