This adds a GISelValueTrackingPrinterPass that can print the known bits
and sign bit of each def in a function. It is built on the new pass
manager and so adds a NPM GISelValueTrackingAnalysis, renaming the older
class to GISelValueTrackingAnalysisLegacy.

The first 2 functions from the AArch64GISelMITest are ported over to an
mir test to show it working. It also runs successfully on all files in
llvm/test/CodeGen/AArch64/GlobalISel/*.mir that are not invalid. It can
hopefully be used to test GlobalISel known bits analysis more directly
in common cases, without jumping through the hoops that the C++ tests
requires.

- Remove calls to pass initialization from pass constructors.
- https://github.com/llvm/llvm-project/issues/111767

- rename `GISelKnownBits` to `GISelValueTracking` to analyze more than
just `KnownBits` in the future

(This replaces #121740. Sorry for wasting your time.)

This is a follow-up to a previous commit (ee7ca0d) which eliminated
several "TODO: make CombinerHelper methods const" remarks. As promised
in that ealier commit, this change completes the set by also making the
methods of AMDGPUCombinerHelper const so that the Helper member of
AMDGPUPreLegalizerCombinerImpl can be const rather than explicitly
mutable.

This combine pattern perform the below transformation.

fmul x, select(y, A, B)      -> fldexp (x, select i32 (y, a, b))
fmul x, select(y, -A, -B)   -> fldexp ((fneg x), select i32 (y, a, b))

where, A=2^a & B=2^b ; a and b are integers.

It is a follow-up PR to implement the above combine for globalIsel, as
the corresponding DAG combine has been done for SelectionDAG Isel
(#111109)

Disable fixed-point iteration in all AMDGPU Combiners after #102163.

This saves around 2% compile time in ad hoc testing on some large
graphics shaders. I did not notice any regressions in the generated
code, just a bunch of harmless differences in instruction selection and
register allocation.

Prepare for new pass manager version of `MachineDominatorTreeAnalysis`.
We may need a machine dominator tree version of `DomTreeUpdater` to
handle `SplitCriticalEdge` in some CodeGen passes.