Don't run integration tests on netcoreapp2.1

[andrewlock]

Summary of changes

Disables the netcoreapp2.1 integration tests

Reason for change

#6498 broke the .NET Core 2.1 integration tests, due to a strange "missing dependency" issue. I believe this is due to the somewhat frankenstein approach we have to building and restoring right now. I hope to improve this in the near future, but fixing it for 2.1 right now is too big of a cost.

Implementation details

Remove 2.1 from the tests

Test coverage

A lot less now unfortunately, but it's not "supported" anyway

Other details

This is the quickest, easiest, way to remove the 2.1 tests to fix the build. Later we can decide if this is the permanent solution we want (in which case we can stop building for 2.1 too) or if we want/can reenable some of the basic tests at least.

[datadog-ddstaging]

Datadog Report

Branch report: andrew/ci/disable-21-integration-tests
Commit report: 0254590
Test service: dd-trace-dotnet

✅ 0 Failed, 251458 Passed, 1983 Skipped, 18h 51m 10.9s Total Time

[andrewlock]

Execution-Time Benchmarks Report ⏱️

Execution-time results for samples comparing the following branches/commits:

• This PR (6560)
• master

Execution-time benchmarks measure the whole time it takes to execute a program. And are intended to measure the one-off costs. Cases where the execution time results for the PR are worse than latest master results are shown in red. The following thresholds were used for comparing the execution times:

• Welch test with statistical test for significance of 5%
• Only results indicating a difference greater than 5% and 5 ms are considered.

Note that these results are based on a single point-in-time result for each branch. For full results, see the dashboard.

Graphs show the p99 interval based on the mean and StdDev of the test run, as well as the mean value of the run (shown as a diamond below the graph).

gantt
    title Execution time (ms) FakeDbCommand (.NET Framework 4.6.2) 
    dateFormat  X
    axisFormat %s
    todayMarker off
    section Baseline
    This PR (6560) - mean (69ms)  : 65, 73
     .   : milestone, 69,
    master - mean (69ms)  : 66, 72
     .   : milestone, 69,

    section CallTarget+Inlining+NGEN
    This PR (6560) - mean (985ms)  : 961, 1008
     .   : milestone, 985,
    master - mean (981ms)  : 959, 1004
     .   : milestone, 981,

Loading

gantt
    title Execution time (ms) FakeDbCommand (.NET Core 3.1) 
    dateFormat  X
    axisFormat %s
    todayMarker off
    section Baseline
    This PR (6560) - mean (107ms)  : 105, 110
     .   : milestone, 107,
    master - mean (108ms)  : 106, 110
     .   : milestone, 108,

    section CallTarget+Inlining+NGEN
    This PR (6560) - mean (677ms)  : 663, 692
     .   : milestone, 677,
    master - mean (680ms)  : 662, 698
     .   : milestone, 680,

Loading

gantt
    title Execution time (ms) FakeDbCommand (.NET 6) 
    dateFormat  X
    axisFormat %s
    todayMarker off
    section Baseline
    This PR (6560) - mean (91ms)  : 88, 93
     .   : milestone, 91,
    master - mean (91ms)  : 89, 93
     .   : milestone, 91,

    section CallTarget+Inlining+NGEN
    This PR (6560) - mean (631ms)  : 617, 644
     .   : milestone, 631,
    master - mean (637ms)  : 617, 657
     .   : milestone, 637,

Loading

gantt
    title Execution time (ms) HttpMessageHandler (.NET Framework 4.6.2) 
    dateFormat  X
    axisFormat %s
    todayMarker off
    section Baseline
    This PR (6560) - mean (190ms)  : 186, 195
     .   : milestone, 190,
    master - mean (190ms)  : 186, 194
     .   : milestone, 190,

    section CallTarget+Inlining+NGEN
    This PR (6560) - mean (1,095ms)  : 1066, 1124
     .   : milestone, 1095,
    master - mean (1,091ms)  : 1062, 1119
     .   : milestone, 1091,

Loading

gantt
    title Execution time (ms) HttpMessageHandler (.NET Core 3.1) 
    dateFormat  X
    axisFormat %s
    todayMarker off
    section Baseline
    This PR (6560) - mean (277ms)  : 273, 280
     .   : milestone, 277,
    master - mean (276ms)  : 271, 280
     .   : milestone, 276,

    section CallTarget+Inlining+NGEN
    This PR (6560) - mean (864ms)  : 838, 890
     .   : milestone, 864,
    master - mean (865ms)  : 838, 892
     .   : milestone, 865,

Loading

gantt
    title Execution time (ms) HttpMessageHandler (.NET 6) 
    dateFormat  X
    axisFormat %s
    todayMarker off
    section Baseline
    This PR (6560) - mean (265ms)  : 259, 271
     .   : milestone, 265,
    master - mean (263ms)  : 259, 267
     .   : milestone, 263,

    section CallTarget+Inlining+NGEN
    This PR (6560) - mean (843ms)  : 804, 881
     .   : milestone, 843,
    master - mean (844ms)  : 813, 875
     .   : milestone, 844,

Loading