Update internal uses of BlockStmt::blockInfoGet/Set to be ForLoop::forInfoGet/Set (transitional)
Drop unused constructor and alter argument order on primary constructor
ForLoop::codegen is now unreachable; delete transitional implementation
Introduce indexGet() and iteratorGet() to replace forInfoGet()
Update the simple calls to forInfoGet to use indexGet/iteratorGet
Update simple uses of forInfoGet and add printf's to investigate tricky cases
Convert references to blockInfo->parentSymbol to forLoop->parentSymbol
Update use of ForLoop::forInfoGet() to indexGet()/iteratorGet()
Update ForLoop::forInfoSet and minor tuning in transitional implementation of ForLoop
Merge pull request #940 from noakesmichael/forLoop-1

Transition away from blockInfoGet/Set for ForLoop

1) Update internal uses of BlockStmt::blockInfoGet/Set to ForLoop::forInfoGet/Set

2) Update external uses of ForLoop::forInfoGet() to ForLoop::indexGet() and ForLoop::iteratorGet()

3) Other minor cleanup for ForLoop

Compiled: STD clang/darwin, STD gcc/linux64, LLVM gcc/linux64
Tested: paratest --verify
Review: None