RFR: 8311020: Typo cleanup in Classfile API [v2]

[Chen Liang]

> This is a cleanup patch that fixes:
> 1. `ClassfileBuilder` should be sealed but was not; it's now sealed.
> 2. Various typo fixes, including spelling errors, wrong descriptions, and unnecessary full qualifications for classes in the same package.
> 
> Requesting a review from @asotona. There's a few other more complex issues discovered, which I will describe on the mailing list to elicit a discussion for best solutions.

Chen Liang has updated the pull request incrementally with one additional commit since the last revision:

  Fix classfile test typos detected by IDE, fix tests

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/14687/files
  - new: https://git.openjdk.org/jdk/pull/14687/files/e2dd9184..675774b5

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=14687&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=14687&range=00-01

  Stats: 7 lines in 2 files changed: 0 ins; 0 del; 7 mod
  Patch: https://git.openjdk.org/jdk/pull/14687.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14687/head:pull/14687

PR: https://git.openjdk.org/jdk/pull/14687