Don't try to split weird critical edges that really aren't:

BB#1: derived from LLVM BB %bb.nph28
    Live Ins: %AL
    Predecessors according to CFG: BB#0
	TEST8rr %reg16384<kill>, %reg16384, %EFLAGS<imp-def>; GR8:%reg16384
	JNE_4 <BB#2>, %EFLAGS<imp-use,kill>
	JMP_4 <BB#2>
    Successors according to CFG: BB#2 BB#2

These double CFG edges only ever occur in bugpoint-generated code, so there is
no need to attempt something clever.

llvm-svn: 117992