Fix -data-evaluate-expression for array.

Summary:
For an array declared like "blk[2][3]", this command was showing:
-data-evaluate-expression blk
^done,value="{[0] = [3], [1] = [3]}"

After this fix, it shows:
-data-evaluate-expression blk
^done,value="{[0] = {[0] = 1, [1] = 2, [2] = 3}, [1] = {[0] = 4, [1] = 5, [2] = 6}}"

The code to do the right thing was already available and used by other commands.
So I have just used that and removed the half-baked previous implementation.

Reviewers: ki.stfu

Subscribers: lldb-commits

Differential Revision: http://reviews.llvm.org/D12634

llvm-svn: 246965