RFR: 8278532: Fix some typos in C1 comments

[Hamlin Li]

This is a trivial patch to fix some typos in C1 comments.

-------------

Commit messages:
 - Initial commit

Changes: https://git.openjdk.java.net/jdk/pull/6793/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=6793&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8278532
  Stats: 5 lines in 3 files changed: 0 ins; 0 del; 5 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6793.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6793/head:pull/6793

PR: https://git.openjdk.java.net/jdk/pull/6793