Make lazyload_metadata.ll resilient to the addition of new metadata kinds

Summary: The specific number of records loaded depends on the number of kinds, but the difference between the lazy and not lazy cases does not.

Reviewers: modocache

Subscribers: mehdi_amini, hiraditya, steven_wu, dexonsmith, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D71730