Sema: incorrectly compares optional floats at comptime

[jacobly0]

const nan = @import("std").math.nan;
comptime {
    @compileLog(nan(f32) == nan(f32));
    @compileLog(@as(?f32, nan(f32)) == @as(?f32, nan(f32)));
}

$ zig build-obj repro.zig
repro.zig:3:5: error: found compile log statement
    @compileLog(nan(f32) == nan(f32));
    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Compile Log Output:
@as(bool, false)
@as(bool, true)

As an added bonus for fixing this bug, you can delete the lines in test/behavior/x86_64/math.zig referencing this issue!