P22 adds the official JAL test

P22 widens P21 from twenty-three official tests to twenty-four by adding I-jal-00.S.

Command:

make -C projects/22_rv32i_jal_tests/test

Result: PASS

Summary: PASS=24 FAIL=0 NOT RUN=0

The new useful mechanism is a reference-emulated signature path. For JAL, the runner builds the upstream test in normal signature-writing mode, runs that image through a small RV32I interpreter, reads the signature words, and then uses those words for the self-check image.

That avoids hand-modeling every forward and backward alignment block in the generated test source.