Prevent autocompilation of the guile test scripts

There were several issues:
- we store the compiled test*.go files in a tests subdirectory, but this is not
  on the GUILE_LOAD_COMPILED_PATH. Added this directory to the path.
- guile was looking for 'script.scm.go' while we create 'script.go'. This is due
  to how we invoke the scripts: guile -l path-to-script.scm -c (something)
  we can replace this with -l path-to-script (without extension) as -l won't add
  the extension. So I've rewrittin the test command to invoke (load-from-path).
- the test modules foo.scm, bar.scm and baz.scm should go in tests/gnucash
  as they are defined as modules (gnucash foo), (gnucash bar) and (gnucash baz)
  respectively.
- find html.scm/go on the load path instead of using a relative path.

libgnucash/gnc-module/test/mod-bar/CMakeLists.txt

@@ -19,6 +19,13 @@ target_include_directories(gncmod-bar PRIVATE
   ${GUILE_INCLUDE_DIRS}
 )
 
+gnc_add_scheme_test_targets(scm-mod-bar
+  gnucash/bar.scm
+  "tests/gnucash"
+  gncmod-bar
+  FALSE
+  )
+
 set_target_properties(bar gncmod-bar PROPERTIES
   LIBRARY_OUTPUT_DIRECTORY ${LIBDIR_BUILD}/gnucash/test
   ARCHIVE_OUTPUT_DIRECTORY ${LIBDIR_BUILD}/gnucash/test

libgnucash/gnc-module/test/mod-baz/CMakeLists.txt

@@ -27,9 +27,9 @@ target_include_directories(gncmod-baz PRIVATE
 
 gnc_add_scheme_test_targets(scm-mod-baz
   gnucash/baz.scm
-  "tests"
+  "tests/gnucash"
   gncmod-baz
-  TRUE
+  FALSE
   )
 
 set_target_properties(baz gncmod-baz PROPERTIES

libgnucash/gnc-module/test/mod-foo/CMakeLists.txt

@@ -21,9 +21,9 @@ target_include_directories(gncmod-foo PRIVATE
 
 gnc_add_scheme_test_targets(scm-mod-foo
   gnucash/foo.scm
-  "tests"
+  "tests/gnucash"
   gncmod-foo
-  TRUE
+  FALSE
   )
 
 set_target_properties(foo gncmod-foo PROPERTIES