Run linker on internal asm tests

[piotro888]

Linker run was somehow missing for our internal assembly tests.
I created basic linker flow (with slightly modified script from our riscv-tests env).

It is needed to run asm test that I written for testing exceptions.

la (load address) instruction is example that doesn't work without linking.
la translates to:
before:

10:   00000317                auipc   t1,0x0
14:   00030313                mv      t1,t1

after:

10000010:       00000317                auipc   t1,0x0
10000014:       02430313                addi    t1,t1,36 # 10000034 <exception_handler>

[tilk]

If I understand things correctly, the data and BSS segments are currently not used, as is the memory map. I believe that the linker script can be simplified, so that it does not suggest that these features work.

[piotro888]

I updated it to minimal that makes sense for me. I also kept the .bss support (but removed .data), because it is already supported in test hardware (just uninitialized memory space) and may be useful for writing tests.