[Instrumentation.Runtime] Remove gc.heap.fragmentation.size metrics due to buggy API on .NET 6

[xiang17]

Removing this metrics because of the same issue #496. Unfortunately there is no convenient alternative API for this metric.

For significant contributions please make sure you have completed the following items:

• Appropriate CHANGELOG.md updated for non-trivial changes
• Design discussion issue Use GC.GetGCMemoryInfo().GenerationInfo[i].SizeAfterBytes for .NET 7 #496

[codecov]

Codecov Report

Merging #509 (43e30f9) into main (db3c2a2) will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff          @@
##            main    #509   +/-   ##
=====================================
  Coverage   0.00%   0.00%           
=====================================
  Files        167     167           
  Lines       5098    5077   -21     
=====================================
+ Misses      5098    5077   -21     

Impacted Files	Coverage Δ
...elemetry.Instrumentation.Runtime/RuntimeMetrics.cs	0.00% <ø> (ø)

[cijothomas]

Could we add net7.0 target to the tests project and validate this as well?

[xiang17]

Could we add net7.0 target to the tests project and validate this as well?

I validated locally for .NET 7.0. However both the runtime library and the test project have to have net7.0 as target. If the runtime library doesn't have net7.0, the src\OpenTelemetry.Instrumentation.Runtime\bin\Debug folder won't have binaries for net7.0, and #if NET7_0_OR_GREATER is never true in any compiled binaries.

[cijothomas]

Could we add net7.0 target to the tests project and validate this as well?

I validated locally for .NET 7.0. However both the runtime library and the test project have to have net7.0 as target. If the runtime library doesn't have net7.0, the src\OpenTelemetry.Instrumentation.Runtime\bin\Debug folder won't have binaries for net7.0, and #if NET7_0_OR_GREATER is never true in any compiled binaries.

Then its best to not rely on compiler preprocessor directives. You should switch to using Environment.Version to detect .NET 6 vs .NET 7, so that this can be used in .NET 7 apps right now.

[xiang17]

Could we add net7.0 target to the tests project and validate this as well?

I validated locally for .NET 7.0. However both the runtime library and the test project have to have net7.0 as target. If the runtime library doesn't have net7.0, the src\OpenTelemetry.Instrumentation.Runtime\bin\Debug folder won't have binaries for net7.0, and #if NET7_0_OR_GREATER is never true in any compiled binaries.

Then its best to not rely on compiler preprocessor directives. You should switch to using Environment.Version to detect .NET 6 vs .NET 7, so that this can be used in .NET 7 apps right now.

Added it back in #524.