Comparison operators for numbers and floats do not handle @nan@ correctly

[tethal]

For more details see comments in #910

From mpfr_cmp documentation:

If one of the operands is NaN, set the erange flag and return zero.

Qore ignores the erange flag and interprets the zero return value as 'equal' (qore_number_private.h:261)

[tethal]

float version of the operators do not work either:

printf("%s\n", @nan@ < 1.0);
printf("%s\n", @nan@ <= 1.0);
printf("%s\n", @nan@ == 1.0);
printf("%s\n", @nan@ != 1.0);
printf("%s\n", @nan@ === 1.0);
printf("%s\n", @nan@ !== 1.0);
printf("%s\n", @nan@ > 1.0);
printf("%s\n", @nan@ >= 1.0);

Produces (all should be False):

0
1
0
1
0
1
0
1

[tethal]

As part of this issue, we should also check:

• that @inf@n is greater than any other number except @inf@n == @inf@n and @inf@n != @nan@n
• that -@inf@n is less than any other number except -@inf@n == -@inf@n and -@inf@n != @nan@n
• similar for floats
• also check comparisons of numbers to floats and ints

[tethal]

Also:

qore -nX '1 == @nan@n'
True
qore -nX '1.0 == @nan@n'
True