info hangs in forward_move_node_structure on malformed input file

[Nathaniel Beaver]

Steps to reproduce:

$ info -f ./hang_002.info.gz
# Press 'Tab' key three times to try to jump to 'Index' node.

Expected behavior:

info shows error "Cannot find node 'Inde'" but does not enter an 
infinite loop.

Actual behavior:

info shows error "Cannot find node 'Inde'" and then enters an infinite loop.

Discussion:

The malformed input file hang_002.info.gz has the 'x' missing from 
"Index", like this:

File: example.info,  Node: First Chapter,  Next: Inde,  Prev: Top,  Up: Top

Version:

$ git describe --tags
texinfo-6.6-364-g63711e8c6
$ git rev-parse HEAD
63711e8c6fafe9b3cde2a2d0be507032d7ee7bf6

Sincerely,

Nathaniel Beaver

hang_002.info.gz
Description: application/gzip

gdb.txt
Description: Text document

example.info.gz
Description: application/gzip