regexp_like using wildcard prefix/suffix without anchors is unoptimized

Take the query, `REGEXP_LIKE(direct_tags, '^.*"key":[^\]]*"value".*$'))` which searches for some array element = "value" in array "key". This query, and the minimized syntax `REGEXP_LIKE(direct_tags, '"key":[^\]]*"value"'))` are both performant.

But when the anchors are dropped like so, `REGEXP_LIKE(direct_tags, '.*"key":[^\]]*"value".*'))`, the query times out on very small numbers of documents.

As a user it's difficult to tell why some regexp patterns are so slow. I think this is a regexp library 'bug', but since prefixing/suffixing a search string with `.*` is a common user behavior it seems to make sense to optimize this.