Check for metadata before getting a value for the sampler.
Check for metadata before getting a value for the sampler.

Followup to r1835351. The eager evaluating led to test failures.
It would probably better to store a zero as Integer and Long instead of
calling Long#valueOf(0L) each time we need a zero.

Bugzilla Id: 62426


git-svn-id: 5ccfe34f605a6c2f9041ff2965ab60012c62539a@1835661 13f79535-47bb-0310-9956-ffa450edef68

vherilier/jmeter,etnetera/jmeter,ubikloadpack/jmeter,ubikloadpack/jmeter,etnetera/jmeter,etnetera/jmeter,vherilier/jmeter,etnetera/jmeter,ubikloadpack/jmeter,ubikloadpack/jmeter,vherilier/jmeter,etnetera/jmeter,vherilier/jmeter