Improve profiled casts

[EgorBo]

For profiled casts, we currently give up on negative cases (when profiled type is never of the casted interface). This PR fixes that, benchmark:

object _obj = 42;

[Benchmark]
public bool IsInterface() => _obj is ICollection or IDisposable;

|      Method |     Mean |    Error |   StdDev |
|------------ |---------:|---------:|---------:|
| IsInterface | 13.80 ns | 1.975 ns | 0.108 ns | Main
| IsInterface |  0.39 ns | 0.029 ns | 0.002 ns | PR

(with DOTNET_JitProfileCasts=1)

Basically, we expand it as obj == null ? null : (obj.GetType() == typeof(int) ? null : helperCall()) (for each isinst)

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Issue Details

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For profiled casts, we currently give up on negative cases (when profiled type is never of the casted interface). This PR fixes that, benchmark:

object _obj = 42;

[Benchmark]
public bool IsInterface() => _obj is ICollection or IDisposable;

Method	Mean	Error	StdDev
IsInterface	13.80 ns	1.975 ns	0.108 ns
IsInterface	0.39 ns	0.0287 ns	0.0016 ns

Basically, we expand it as _obj.GetType() == typeof(int) ? null : helperCall (for each isinst)

Author:	EgorBo
Assignees:	-
Labels:	area-CodeGen-coreclr
Milestone:	-

[EgorBo]

/azp run runtime-coreclr pgo, runtime-coreclr libraries-pgo, runtime-coreclr pgostress

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Azure Pipelines successfully started running 3 pipeline(s).

[EgorBo]

@AndyAyersMS PTAL, small change to the "not-yet-enabled-by-default" cast profiling.

[EgorBo]

Failures are #90593