Test harness implicitly assumes expected memory layout

[danmatichuk]

The test binaries are all compiled with a linker script that places "observable" memory in an expected section. The location of this section is hard-coded into the test module for each architecture. The size of the section is assumed to be 4k (which essentially assumes that the section is placed after any non-observable memory).

Ideally this information could be read from the ELF file rather than being hard-coded (i.e. the testbench only relies on the existence of a specially-named observable memory section).