Allow for 5200 words in dump-words-to-file

After switching to OpenJdk,  doc-comment-check target
started to fail due to "Too many words (5082)" while
generating out/target/common/docs/doc-comment-check-timestamp.rsp
This change extends number of dumped words to 5200.

Bug: 25758743

(cherry picked from commit 972a2681)

Change-Id: I9b8516d1e7c113d667dcfb7963ee352972677afa