Merge branch 'drop-gitignore' into 'main'

build: Drop old .gitignore files from test directories

See merge request GNOME/glib!3333

gobject/tests/.gitignore

@@ -1,18 +0,0 @@
-binding
-boxed
-closure
-dynamictests
-enums
-ifaceproperties
-object
-param
-properties
-qdata
-reference
-signal-handler
-signals
-threadtests
-type
-value
-private
-marshalers.[ch]