change testing glob to be windows compatible

[dyladan]

The previous glob failed on windows machines.

[codecov-io]

Codecov Report

Merging #784 into master will decrease coverage by 0.19%.
The diff coverage is n/a.

@@            Coverage Diff            @@
##           master     #784     +/-   ##
=========================================
- Coverage   91.26%   91.07%   -0.2%     
=========================================
  Files         235      100    -135     
  Lines       10882     4942   -5940     
  Branches     1027      498    -529     
=========================================
- Hits         9932     4501   -5431     
+ Misses        950      441    -509

Impacted Files	Coverage Δ
...-api/test/noop-implementations/noop-tracer.test.ts	60% <0%> (-40%)	⬇️
...ry-api/test/noop-implementations/noop-span.test.ts	63.63% <0%> (-36.37%)	⬇️
.../opentelemetry-api/src/trace/NoopTracerProvider.ts	40% <0%> (-40%)	⬇️
...ntelemetry-exporter-stackdriver-trace/src/types.ts	100% <0%> (ø)	⬆️
...s/opentelemetry-plugin-xml-http-request/src/xhr.ts	79.41% <0%> (ø)	⬆️
...ntelemetry-exporter-stackdriver-trace/src/trace.ts	95.83% <0%> (ø)	⬆️
...entelemetry-plugin-dns/src/enums/AttributeNames.ts	100% <0%> (ø)	⬆️
...ry-plugin-dns/test/functionals/dns-disable.test.ts	100% <0%> (ø)	⬆️
packages/opentelemetry-plugin-dns/src/version.ts	100% <0%> (ø)	⬆️
...emetry-plugin-xml-http-request/src/enums/Format.ts	100% <0%> (ø)	⬆️
... and 203 more