Fix whitespace in the bigbench

[Red-Caesar]

The condition to break the loop has not worked before if there is leading whitespace in the token.

[Red-Caesar]

Usually, for loglikelihood tasks, two arguments are used: context and continuation. Together, they are submitted as a single query in the LLM for calculation: context + continuation. In all benchmarks, the context doesn't have a space at the end, while the continuation starts with one. For example:

context="A:"
continuation=" zero"

However, it was found that in BigBench, the spaces are the opposite:

context="A: "
continuation="zero"

This disrupts the logic of calculating loglikelihood in the harness.

New mesaurements of the bigbench will be here