By Hyonhee Shin SEOUL (Reuters) -North Korea test-fired what it says was a new intermediate-range ballistic missile (IRBM) on Sunday, in what would be its first such missile powered by solid fuel designed boost capabilities for launching with little preparation. The new missile was also equipped with a hypersonic manoeuvrable controlled warhead, state media said. The launch comes after the nuclear-armed North said it had tested solid-fuel engines for an upcoming new-type IRBM in November, and conducted at least three tests last year of its new solid-fuel Hwasong-18 intercontinental ballistic m…