Fix sym name cache: handles the difference between text and data, + match in symbol

Fix sym name cache: handles the difference between text and data, + match in symbol
* sym name cache to cache the 'isText' characteristic of the cached sym_name
* implement the match anywhere also in the cache
Not handling matchAnywhere has bad performance effect on callgrind, as almost many
IPs were considered as a fn entry, while they were not.
* use the same convention to name the findText argument

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@16136