[RenderScript] New commands to save/load RS allocations to file.

Patch adds command 'language renderscript allocation save' to store the contents of an allocation in a binary file.
And 'language renderscript allocation load' to restore an allocation with the saved data from a binary file.

Binary file format contains a header FileHeader with meta information preceding the raw data.


Reviewed by: jingham, clayborg
Subscribers: lldb-commits, domipheus
Differential Revision: http://reviews.llvm.org/D13903

llvm-svn: 250886