RFR: JDK-8189861: Refactor CacheFind

[Tim Bell]

Erik:

> The macro CacheFind is a bit awkward to use with FillCacheFind. The
> naming is also not that great. This patch tries to improve this
> situation. The main difference is naming of the macros. Now the main
> entry point is "FindFiles". There are a couple of others as well, see
> MakeBase.gmk for details. Another notable difference is that
> FillCacheFind is now called FillFindCache and should not be called with
> $(eval) anymore.
>
> As an alternative to running $(shell find ...), I have implemented a
> recursive macro using $(wildcard ...) that mimics the basic FindFiles
> functionality. I have found that on Windows/Cygwin, it's generally a bit
> faster than spawning external processes. With this change, the default
> FindFiles will use the wildcard find macro on Windows.
>
> My initial idea for this patch was to essentially get rid of
> FillFindCache and have FindFiles add everything to the cache
> automatically. Unfortunately, that did not do anything to improve
> performance as in the large majority of cases, we do not reuse find
> results. I think it's better to explicitly cache things in the few
> locations where it actually helps.
>
> I have added a decent set of tests in TestMakeBase.gmk that verifies the
> functionality of the new macros.
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8189861
> <https://bugs.openjdk.java.net/browse/JDK-8189861?filter=-1>
>
> Webrev: http://cr.openjdk.java.net/~erikj/8189861/webrev.01/index.html

Looks good.

Tim