Issue:
  During parsing of a call statement, tokens from sub statements were 
  getting considered as well because of which tokens collection of 
  'call statement' was getting affected. So, due to these extra unwanted 
  tokens, digest generated for call statement, was different from the 
  further calls of same call statement where sub statements were not 
  parsed again.
      
Resolution:
  Restrict collection of token for only top-level statement. i.e. no 
  instrumentation for sub-statements.