debug-text-hashfunctions: Test suite for content hashes

This is the test suite I was using to help understand why we had
such a high collision rate with RawTextComparator, and to select
a replacement function.

Since its not something we will run very often, lets make it a
program in the debug package rather than a JUnit test.  This way
we can run it on demand against any corpus of files we choose,
but we aren't bottlenecking our daily builds running tests with
no assertions.

Adding a new hash function to this suite is simple, just define
a new instance member of type "Hash" with the logic applied to
the region passed in.

Change-Id: Iec0b176adb464cf95b06cda157932b79c0b59886
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
2 files changed