Stop checking attributes for UTF-8 validity
I can't see a reason to check attribute content for UTF-8 validity.
Other parts of the API like xmlNewText have always assumed valid UTF-8
as extra checks only slow down processing.
Besides, setting doc->encoding to "ISO-8859-1" seems pointless, and not
freeing the old encoding would cause a memory leak.
Note that this was last changed in 2008 with commit 6f8611fd which
removed unnecessary encoding/decoding steps. Setting attributes should
be even faster now.
Found by OSS-Fuzz.
1 file changed
