Fix failing ContentProfileErrorReportUtilsTest

The tests were failing if the test methods' order is changed.
It is because the flag value is stored in a static variable
which doesn't change until BT process ends.
This CL removes the static variable.

Also this CL makes the ContentProfileErrorReportUtilsTest.report()
return a boolean representing the result.

Bug: 317002318
Bug: 294797589
Test: atest ContentProfileErrorReportUtilsTest
      (Also tested changing test methods' order)
Change-Id: I5e63d0bf7dd694caec38c1360ec1372ddf77e00c