Move type check of MD array to managed

[huoyaoyuan]

Removes a HELPER_METHOD_FRAME.

Generally there are more of MD array can be moved to managed, but not completely now.

Method	Job	Toolchain	Mean	Error	StdDev	Ratio	RatioSD
SetCovariant	Job-KZUIWY	\PR\corerun.exe	2.758 ns	0.0252 ns	0.0236 ns	0.99	0.01
SetCovariant	Job-ZSCMRL	\main\corerun.exe	2.780 ns	0.0191 ns	0.0169 ns	1.00	0.00
SetExactMatch	Job-KZUIWY	\PR\corerun.exe	2.768 ns	0.0323 ns	0.0302 ns	0.99	0.02
SetExactMatch	Job-ZSCMRL	\main\corerun.exe	2.795 ns	0.0246 ns	0.0230 ns	1.00	0.00

Not over optimizing, just ensuring no regression.

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[huoyaoyuan]

It seems that we are ready to enable it for all platforms. Just separating to another PR.

[jkotas]

I agree it would be nice to enable this on all platforms and delete the #define.

[jkotas]

Not over optimizing, just ensuring no regression.

Could you please share the source for the benchmark? It is a bit suspicious that the difference between the baseline and the PR is in the noise range. I would expect it to be a small measurable improvement.

[jkotas]

LGTM otherwise. Thank you!

[huoyaoyuan]

Updated test:

        private Base[,] baseArray = new Base[10, 1];
        private Base[,] covariantArray = new Derived[10, 1];
        private Derived[,] derivedArray = new Derived[10, 1];

        private Derived derivedObj = new Derived();

        private void GenericSet<T>(T[,] array, T value)
        {
            for (int i = 0; i < 10; i++)
            {
                array[i, 0] = value;
            }
        }

        [Benchmark]
        public void ReferenceTypeBase() => GenericSet(baseArray, derivedObj);

        [Benchmark]
        public void ReferenceTypeExactMatch() => GenericSet(derivedArray, derivedObj);

        [Benchmark]
        public void ReferenceTypeCovariant() => GenericSet(covariantArray, derivedObj);

Result:

Method	Job	Toolchain	Mean	Error	StdDev	Ratio	RatioSD
ReferenceTypeBase	Job-IECQRX	\PR\corerun.exe	32.91 ns	0.183 ns	0.171 ns	0.76	0.01
ReferenceTypeBase	Job-OMBWNE	\main\corerun.exe	43.08 ns	0.219 ns	0.194 ns	1.00	0.00
ReferenceTypeExactMatch	Job-IECQRX	\PR\corerun.exe	29.27 ns	0.422 ns	0.395 ns	1.00	0.02
ReferenceTypeExactMatch	Job-OMBWNE	\main\corerun.exe	29.13 ns	0.342 ns	0.320 ns	1.00	0.00
ReferenceTypeCovariant	Job-IECQRX	\PR\corerun.exe	28.59 ns	0.229 ns	0.214 ns	1.00	0.01
ReferenceTypeCovariant	Job-OMBWNE	\main\corerun.exe	28.68 ns	0.181 ns	0.169 ns	1.00	0.00

Yes it is measuable improvement when array.GetType().ElementType isn't exact obj.GetType(). The static type of array doesn't matter here.