This patch adds support for the shift operators to handle non-constant
shift operands.

ashr proof -->https://alive2.llvm.org/ce/z/EN-siK
lshr proof --> https://alive2.llvm.org/ce/z/eeGzyB
shl proof --> https://alive2.llvm.org/ce/z/dpvbkq

Seeing how we can't generate any debug intrinsics any more: delete a
variety of codepaths where they're handled. For the most part these are
plain deletions, in others I've tweaked comments to remain coherent, or
added a type to (what was) type-generic-lambdas.

This isn't all the DbgInfoIntrinsic call sites but it's most of the
simple scenarios.

Co-authored-by: Nikita Popov <github@npopov.com>

Having a finite Depth (or recursion limit) for computeKnownBits is very
limiting, but is currently a load-bearing necessity, as all KnownBits
are recomputed on each call and there is no caching. As a prerequisite
for an effort to remove the recursion limit altogether, either using a
clever caching technique, or writing a easily-invalidable KnownBits
analysis, make the Depth argument in APIs in ValueTracking uniformly the
last argument with a default value. This would aid in removing the
argument when the time comes, as many callers that currently pass 0
explicitly are now updated to omit the argument altogether.

Identified with misc-include-cleaner.

This is a helper to avoid writing `getModule()->getDataLayout()`. I
regularly try to use this method only to remember it doesn't exist...

`getModule()->getDataLayout()` is also a common (the most common?)
reason why code has to include the Module.h header.

This reverts commit b5743d4798b250506965e07ebab806a3c2d767cc.

This causes some minor compile-time impact. Revert for now, better
to do the change more gradually.

Remove the old overloads that accept KnownBits by reference, in
favor of those that return it by value.

Include the function name + analysis when printing the analysis for
testing.

Last user of DemandedBitsWrapperPass was the BDCE pass. Since
the legacy PM version of BDCE was removed in an earlier commit, this
patch removes the now unused DemandedBitsWrapperPass.

Differential Revision: https://reviews.llvm.org/D148336