Fix fuzzed filename in long_log

[igor-simoes]

it has been observed that if a file fails more than once, the file long_log.txt must contain the identical name of the fuzzed file to identify that it is another file.

Actual:

***  .../duktape/tests/fuzzed_DukTape_ecmascript_test-bi-date.js
jsc failed
ch pass
sm pass
v8 failed
***  .../duktape/tests/fuzzed_DukTape_ecmascript_test-bi-date.js
jsc pass
ch failed
sm pass
v8 pass

Expected:

***  .../duktape/tests/fuzzed_DukTape_ecmascript_test-bi-date.js
jsc failed
ch pass
sm pass
v8 failed
***  .../duktape/tests/fuzzed_DukTape_ecmascript_test-bi-date_2_.js
jsc pass
ch failed
sm pass
v8 pass