[Object][MachO] Rewrite macho-invalid-fat-arch-size into YAML

Summary:
Rewrite one of the invalid macho test input file with YAML file. The
original invalid macho is breaking our internal test infrastusture
because it is too broken to be copy around.

Need to relax an assertion in the YAML/MachoEmitter to allow yaml2obj to
write an invalid object like this.

rdar://problem/56879982

Reviewers: beanz, mtrent

Reviewed By: beanz

Subscribers: hiraditya, jkorous, dexonsmith, ributzka, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D69856