[analyzer] Consolidate array bound checkers (#125534)

Before this commit, there were two alpha checkers that used different
algorithms/logic for detecting out of bounds memory access: the old
`alpha.security.ArrayBound` and the experimental, more complex
`alpha.security.ArrayBoundV2`.

After lots of quality improvement commits ArrayBoundV2 is now stable
enough to be moved out of the alpha stage. As indexing (and dereference)
are common operations, it still produces a significant amount of false
positives, but not much more than e.g. `core.NullDereference` or
`core.UndefinedBinaryOperatorResult`, so it should be acceptable as a
non-`core` checker.

At this point `alpha.security.ArrayBound` became obsolete (there is a
better tool for the same task), so I'm removing it from the codebase.
With this I can eliminate the ugly "V2" version mark almost everywhere
and rename `alpha.security.ArrayBoundV2` to `security.ArrayBound`.

(The version mark is preserved in the filename "ArrayBoundCheckerV2", to
ensure a clear git history. I'll rename it to "ArrayBoundChecker.cpp" in
a separate commit.)

This commit adapts the unit tests of `alpha.security.ArrayBound` to
testing the new `security.ArrayBound` (= old ArrayBoundV2). Currently
the names of the test files are very haphazard, I'll probably create a
separate followup commit that consolidates this.

1 files changed, 4 insertions, 2 deletions

diff --git a/clang/lib/StaticAnalyzer/Checkers/CStringChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/CStringChecker.cpp
index 1a14f38..39dcaf0 100644
--- a/clang/lib/StaticAnalyzer/Checkers/CStringChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/CStringChecker.cpp
@@ -547,8 +547,10 @@ ProgramStateRef CStringChecker::checkInit(CheckerContext &C,
   }
   return State;
 }
-
-// FIXME: This was originally copied from ArrayBoundChecker.cpp. Refactor?
+// FIXME: The root of this logic was copied from the old checker
+// alpha.security.ArrayBound (which is removed within this commit).
+// It should be refactored to use the different, more sophisticated bounds
+// checking logic used by the new checker ``security.ArrayBound``.
 ProgramStateRef CStringChecker::CheckLocation(CheckerContext &C,
                                               ProgramStateRef state,
                                               AnyArgExpr Buffer, SVal Element,