Rename the fortify compile-time diags test

Following up on comments from I40c66ff9e638b306878ada006bc2c98f2346e77a.
My best attempt at a name that conveys "a test that fails to compile in
N different ways with FORTIFY enabled, and is intended to be used with
either FileCheck, or as a cheap way to check that FORTIFY is getting
properly disabled given some set of flags."

Bug: None
Test: mma.
Change-Id: I6d62875bd1cabc5d01b10ae0f03accd5ee5c8c0a