fix: batchSpanProcessor test failing intermittently

[mayurkale22]

Which problem is this PR solving?

• Resolves BatchSpanProcessor test failing intermittently #350

• This has been verified locally by running regression test, with and w/o the change.

[codecov-io]

Codecov Report

Merging #444 into master will increase coverage by 0.07%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #444      +/-   ##
==========================================
+ Coverage   95.33%   95.41%   +0.07%     
==========================================
  Files         124      124              
  Lines        6071     6173     +102     
  Branches      506      508       +2     
==========================================
+ Hits         5788     5890     +102     
  Misses        283      283

Impacted Files	Coverage Δ
...try-tracing/test/export/BatchSpanProcessor.test.ts	100% <100%> (ø)	⬆️
...ges/opentelemetry-exporter-zipkin/src/transform.ts	100% <0%> (ø)	⬆️
...telemetry-plugin-grpc/test/utils/assertionUtils.ts	100% <0%> (ø)	⬆️
.../opentelemetry-exporter-zipkin/test/zipkin.test.ts	100% <0%> (ø)	⬆️
packages/opentelemetry-metrics/test/Meter.test.ts	100% <0%> (ø)	⬆️
...entelemetry-exporter-zipkin/test/transform.test.ts	100% <0%> (ø)	⬆️