[Installer] Name only the payload programs installed in the directory (#7684)

The running-instance lookup named every process whose image path began with the
install directory, subfolders included. Installing into a folder that holds
another application in a subfolder therefore reported that application as
holding the previous version, and nothing the guard offers could clear it: the
close asks cockatrice.exe only, and the end answer refuses anything that is not
a payload program. Both answers were no-ops, so the update could only abort and
tell the user to close a program that was never touching the files.

Name only the programs the payload installs, and only when the image lies in the
install directory itself. A program below the directory that really does hold a
payload file is still named by the Restart Manager lookup, which is the lookup
for that question.

The Windows probe check now covers a payload-named program in a subfolder and a
program the payload does not install; both have to come back as nothing.

Co-authored-by: Lukas Brübach <Bruebach.Lukas@bdosecurity.de>

tests/CMakeLists.txt

@@ -178,8 +178,9 @@ cockatrice_add_test(NAME user_data_backup_test SOURCES user_data_backup_test.cpp
 cockatrice_add_test(NAME password_hash_test SOURCES password_hash_test.cpp LIBS libcockatrice_utility)
 cockatrice_add_test(NAME report_categories_test SOURCES report_categories_test.cpp LIBS libcockatrice_utility)
 cockatrice_add_test(NAME warning_categories_test SOURCES warning_categories_test.cpp LIBS libcockatrice_utility)
-# The installer's holder probe is Windows-only, but the wording it produces is plain C++
-# and is what a stuck user has to act on, so it is tested everywhere.
+# The installer's holder probe is Windows-only, but the wording it produces and the
+# question which programs are the payload's own are plain C++ and are what a stuck user
+# has to act on, so they are tested everywhere.
 cockatrice_add_test(
   NAME
   holder_line_test
@@ -189,6 +190,15 @@ cockatrice_add_test(
   INCLUDE_DIRS
   ${CMAKE_SOURCE_DIR}/tools/installer-holder-probe
 )
+cockatrice_add_test(
+  NAME
+  payload_paths_test
+  SOURCES
+  ${CMAKE_SOURCE_DIR}/tools/installer-holder-probe/payload_paths.cpp
+  payload_paths_test.cpp
+  INCLUDE_DIRS
+  ${CMAKE_SOURCE_DIR}/tools/installer-holder-probe
+)
 cockatrice_add_test(
   NAME
   playmat_resolver_test