In iterator.cpp convert uses of the blockInfo type with tests on the BlockStmt
Convert a test on blockInfo state to an explicit test on a Loop
Merge pull request #891 from noakesmichael/iter-0

Several of the section constructors in iterators.cpp are specialized for CForLoop.  Convert these
from a reliance on isCForLoop()

Compiled: STD clang/darwin, STD gcc/linux64, LLVM gcc/linux64
Tested: paratest
Review: None