Tidy up tags for CAPI tests.

Author: aardvark179

spec/tags/optional/capi/class_tags.txt

@@ -1,3 +1,2 @@
-fails:C-API Class function rb_call_super calls the method in the superclass through two native levels
 fails(autoload):C-API Class function rb_path2class resolves autoload constants
 fails(autoload):C-API Class function rb_path_to_class resolves autoload constants

spec/tags/optional/capi/kernel_tags.txt

@@ -1,2 +1 @@
 fails(uses-fork):C-API Kernel function rb_set_end_proc runs a C function on shutdown
-fails:C-API Kernel function rb_yield rb_yield to block passed to enumerator

spec/tags/optional/capi/module_tags.txt

@@ -1,4 +1,3 @@
-fails:C-API Struct function rb_struct_define_under returns the member names as Symbols
 fails:C-API Struct function rb_struct_define raises an ArgumentError if arguments contain duplicate member name
 fails:C-API Struct function rb_struct_getmember returns the value of a struct member
 fails:C-API Struct function rb_struct_getmember raises a NameError if the struct member does not exist