Fix assorted JSONPath Comparison tests, vol. 2

[crocodele]

Fixes for making the following uncategorized tests pass:

• comparison_filter/035.phpt: Test filter expression with equals number for array slice with range 1
• comparison_filter/040.phpt: Test filter expression with equals object
• comparison_filter/057.phpt: Test filter expression with regular expression
• comparison_filter/071.phpt: Test filter expression with value from recursive descent
• comparison_root/001.phpt: Test root

[crocodele]

@mkaminski1988, any opinion on the regex syntax – should we stick with quotes around the regex pattern or remove them? Personally I think the expression looks tidier without the quotes, and that's also how most implementations seem to work.

[mk6i]

@crocodele, agreed. Working on support for this in #104.