Replace double/float IsNaN + IsInfinity checks with optimized IsFinite

[h3xds1nz]

Description

Several versions ago, IsFinite was introduced as an intrinsic, therefore there's no need to perform two separate checks for the same thing, it simplifies the code, uses less bytes and the codegen is also smaller and more efficient.

I've also cleaned up some of the unused util methods in that domain.

Simple benchmark

Method	param	Mean [ns]	Error [ns]	StdDev [ns]	Code Size [B]	Allocated [B]
Original	NaN	0.0056 ns	0.0069 ns	0.0065 ns	50 B	-
PR__EDIT	NaN	0.0029 ns	0.0046 ns	0.0043 ns	27 B	-
Original	5	0.1519 ns	0.0082 ns	0.0073 ns	50 B	-
PR__EDIT	5	0.0000 ns	0.0000 ns	0.0000 ns	27 B	-
Original	Infinity	0.1539 ns	0.0091 ns	0.0085 ns	50 B	-
PR__EDIT	Infinity	0.0002 ns	0.0006 ns	0.0006 ns	27 B	-

There are a few places I didn't remove these checks, that should be done separately. Those are constructors that emit different messages for NaN and Infinity. We should have a discussion on how to approach this. As those are all exception cases, ideal approach is probably to create a non-inlinable throw helper that further then checks IsNaN/IsInfinity in case IsFinite already fails and throws the exception with correct messages. Would reduce the ctor complexity for an uncommon case, though it will start to matter a bit less in .NET 10+ as methods with EH frames will now be inlinable.

P.S. That DoubleValue_Validate from DocumentViewer is the real legacy code gem that should have been preserved I guess.

Customer Impact

Improved performance, decreased allocations.

Regression

No.

Testing

Local build.

Risk

Medium, I was doing all of these replacements manually and thus this is rather error-prone where I could invert a condition badly and I didn't notice it. Review carefully this one please, thank you.

Microsoft Reviewers: Open in CodeFlow

[codecov]

Codecov Report

Attention: Patch coverage is 4.41176% with 65 lines in your changes missing coverage. Please review.

Project coverage is 11.06494%. Comparing base (2ded801) to head (8882fa7).

Additional details and impacted files

@@                 Coverage Diff                 @@
##                main      #10690         +/-   ##
===================================================
+ Coverage   10.95887%   11.06494%   +0.10607%     
===================================================
  Files           3310        3310                 
  Lines         664667      664495        -172     
  Branches       74667       74627         -40     
===================================================
+ Hits           72840       73526        +686     
+ Misses        590685      589834        -851     
+ Partials        1142        1135          -7     

Flag	Coverage Δ
Debug	11.06494% <4.41176%> (+0.10607%)	⬆️

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[jizc]

LGTM! Just one comment/question.