Never run the plain highlighter on fuzzy queries

Fuzzy queries are super duper slow on the plain highlighter so just skip
using it for those queries.  This means that queries that use ~ to get
a fuzzy match won't have highlighted headings or redirects but they'll be
much faster and less likely to anger Elasticsearch's CPUs.

In my development environment these queries are ~3700% faster which seems
worth it for missing out on the less used highlighted fields.

Change-Id: I96b1dd736c57ca02c5f98572d553f242cef7a047
Merge "Never run the plain highlighter on fuzzy queries"