[LLD][ELF][test] Fix CHECKs in map-file test

A repeated typo in lld/test/ELF/map-file.s prevented a number of checks from being executed.

CHECk-NEXT -> CHECK-NEXT
    ^             ^

After correcting the typo, a small adjustment was needed to match the size of the synthetic .comment section (which always contains "LLD 1.0" in the test environment).

Differential revision: https://reviews.llvm.org/D88023