Fix -stack-list-locals and -stack-list-arguments (MI)

Summary:
These changes include:
* Add eVariableInfoFormat argument for MIResponseFormVariableInfo{,2,3} and GetVariableInfo{,2} functions
* Fix -stack-list-locals and -stack-list-arguments: they ingored print-values
* Enable MiStackTestCase tests for -stack-list-xxx commands

All test pass on OS X.

Reviewers: abidh, clayborg

Reviewed By: abidh

Subscribers: lldb-commits, clayborg, abidh

Differential Revision: http://reviews.llvm.org/D7462

llvm-svn: 228412