Fixed issues with the dalvik tests scripts when running on Linux.
Fixed a stack "corruption" issue in unwindIterateCallStack(). The
rvmPushGatewayFrame() macro uses a local GatewayFrame variable which is
allocated on the stack. The old version of unwindIterateCallStack() called
rvmPushGatewayFrame() inside an if-block and then did the corresponding
rvmPopGatewayFrame() call outside that block. It seems like the stack used by
the local GatewayFrame in the if-block was reused and overwritten when that
variable went out of scope. Quite reasonable when you think about it. It used
to work in GCC 4.7 and it works with clang but caused a crash with GCC 4.8.
Conclusion: rvmPushGatewayFrame() must be called in the same scope as
rvmPopGatewayFrame() or in a parent scope for this to work properly. The code
in unwindIterateCallStack() has been changed accordingly and a note has been
addd to types.h.