lib: event filter - Avoid using event name wildcard matching when not needed

lib: event filter - Avoid using event name wildcard matching when not needed

If the right hand side of an event name comparison is not using any
wildcards, we can compare using strcmp() instead of the more expensive
wildcard_match().

This wildcard matching avoidance change speeds up matching quite a bit.
When the desired comparison is *not* a wildcard match (i.e., the filter is
'event=abc'), microbenchmarks show at least a 30% speedup in filter matching
speed.  When the comparison includes a wildcard (i.e., the filter is
'event=abc*'), microbenchmarks show approximately 0.4% filer matching
slowdown.

Since there are so many non-wildcard matches in a typical filter, this is a
very good trade-off.