More tests for alex innovation json

Added tests of the JSON function SET_FIELD, plus a few more for FIELD, including with dotted path and/or array index notation, and with dot and bracket characters not used in that way (and therefore escaped with a backslash), and using numeric, floating point data.
There should be some overflow intervention here to guard against "array[100000000000000000000000000000000]" which (I think) will effectively wrap around to "array[0]" instead of erroring out.
One possible method is to accumulate arrayIndex into an int64 and throwInvalidPathError from inside the loop as soon as it exceeds MAX_INT32.