According to this article [1] in Washington Post, the first occurrence of Texas as "crazy" in Norwegian dates to 1957. Makes me wonder if it's used this way in other European countries too, and whether or not the etymology is independent.
It's worth noting that unlike the term "Amerikanske tilstander" ("American conditions") in politics (as shorthand for implying your opponent is pushing for whichever stereotypically bad thing about American politics fits best in the specific policy area), the use of "Texas" refers to wild west movies, and so is about 19th century lawlessness, not modern Texas (though there certainly is still a stereotype of Texas as being at least, well, somewhat Texas)
[1] https://www.washingtonpost.com/news/morning-mix/wp/2015/10/2...