Added Small Problem Size support to most tests in Benchmarks/Polybench/stencil/.

Specifically I added said support for:

1. adi.
2. fdtd-2d.
3. fdtd-apml.
4. jacobi-2d-imper.
5. seidel-2d.

rdar://11907111.

git-svn-id: https://llvm.org/svn/llvm-project/test-suite/trunk@175246 91177308-0d34-0410-b5e6-96231b3b80d8
Turned back on Polybench tests on ARM since we now have Small Problem Size support.

rdar://11907111.

git-svn-id: https://llvm.org/svn/llvm-project/test-suite/trunk@175247 91177308-0d34-0410-b5e6-96231b3b80d8