publish test utils (#442)

Publish `tracing-test-utils`

Author: ferozco

changelog/@unreleased/pr-442.v2.yml

@@ -0,0 +1,5 @@
+type: feature
+feature:
+  description: Publish `tracing-test-utils`
+  links:
+  - https://github.com/palantir/tracing-java/pull/442

tracing-test-utils/build.gradle

@@ -1,5 +1,4 @@
-// temporarily disabling publishing on this so we can iterate further on the API before we commit to something
-// apply from: "${rootDir}/gradle/publish-jar.gradle"
+ apply from: "${rootDir}/gradle/publish-jar.gradle"
 
 versionsLock {
     testProject()