[NFC] Fix formatting for the 'aix-ld.c' test case.

Summary:
Based on comments received in D80415 pertinent to test case format, the following fixes are provided to other tests in 'aix-ld.c' for the sake of consistency and readability,
  - Align flags in RUN directives vertically.
  - Align patterns in CHECK directives vertically.
  - Remove the ‘-o %t.o’ as it’s unnecessary for tests with ‘-###’.
  - Fix typos in comments.

Reviewers: ZarkoCA, hubert.reinterpretcast, daltenty

Reviewed By: hubert.reinterpretcast

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D80532