Linux/ARM: Adding rpath for shared library of exception_handling.pal_sxs.test1 (...

Linux/ARM: Adding rpath for shared library of exception_handling.pal_sxs.test1 (#5328)

Let's add the 'rpath' in order to fix error happened while
'paltest_pal_sxs_test1' (ELF) of PAL test is loading a shared library.
This 'rpath' statement is derived from the existing files such as
./ToolBox/SOS/Strike/CMakeLists.txt and dlls/mscordbi/CMakeLists.txt.

Ver2:
Apply 'rpath' in case of the Linux platform only

Ver1:
Let's add 'rpath' statement to the Linux platform environment
that we have experienced issue.

Signed-off-by: Geunsik Lim <geunsik.lim@samsung.com>
CC: Mike McLaughlin <mikem@microsoft.com>