[InMemoryExporter] Include original stack trace in ObjectDisposedException

[CodeBlanch]

Relates to #3607

Added the stack trace for the original Dispose call to the message when we throw ObjectDisposedException inside the In-memory Exporter (to help track down issues). Fixed a couple flaky tests that helped me track down 😄

/cc @reyang

[codecov]

Codecov Report

Merging #3609 (12ed5a6) into main (372767a) will increase coverage by 0.10%.
The diff coverage is 25.00%.

@@            Coverage Diff             @@
##             main    #3609      +/-   ##
==========================================
+ Coverage   87.15%   87.26%   +0.10%     
==========================================
  Files         277      277              
  Lines        9950     9953       +3     
==========================================
+ Hits         8672     8685      +13     
+ Misses       1278     1268      -10     

Impacted Files	Coverage Δ
...penTelemetry.Exporter.InMemory/InMemoryExporter.cs	81.81% <25.00%> (-12.92%)	⬇️
...ZPages/Implementation/ZPagesExporterEventSource.cs	56.25% <0.00%> (-6.25%)	⬇️
...OpenTelemetry/Metrics/BaseExportingMetricReader.cs	86.15% <0.00%> (-4.62%)	⬇️
...ter.ZPages/Implementation/ZPagesActivityTracker.cs	97.14% <0.00%> (-2.86%)	⬇️
...nTelemetry/Internal/OpenTelemetrySdkEventSource.cs	77.50% <0.00%> (-2.50%)	⬇️
...tpListener/Internal/PrometheusCollectionManager.cs	78.04% <0.00%> (-2.44%)	⬇️
src/OpenTelemetry/Metrics/MetricReader.cs	88.13% <0.00%> (-1.70%)	⬇️
...metryProtocol/Implementation/ActivityExtensions.cs	96.15% <0.00%> (+4.39%)	⬆️
...tation/OpenTelemetryProtocolExporterEventSource.cs	85.00% <0.00%> (+10.00%)	⬆️
...xporter.OpenTelemetryProtocol/OtlpTraceExporter.cs	77.27% <0.00%> (+40.90%)	⬆️
... and 1 more