Findings and brief analysis
Googling about, here's what I've found so far.
過去の否定形 -- 35,400 hits
Of the first page of 10 hits, 6 were about French grammar, one about Mongolian, one about Korean, one about English, and one about Japanese.
否定の過去形 -- 27,200 hits
First 10 hits: 5 about Japanese, two about Ryūkyūan (Okinawan and Miyako), two about Korean, and ...