[AST] NFC: Remove {TokenKinds, Attr}.def.gyb from CMakeLists

Author: xedin

include/swift/AST/CMakeLists.txt

@@ -3,8 +3,3 @@ if(CMAKE_HOST_SYSTEM_NAME STREQUAL "Windows")
 else()
   set(SWIFT_GYB_FLAGS --line-directive "\'#line" "%(line)d" "\"%(file)s\"\'")
 endif()
-
-set(generated_include_sources
-    Attr.def.gyb
-    TokenKinds.def.gyb)
-