cxbe: Fix broken XBE sections sizes

[LoveMHz]

A simple test with the hello world example is enough to generate an XBE with an invalid header.

#include <hal/debug.h>
#include <hal/video.h>
#include <windows.h>

__attribute__((section("TEST")))
void test() {
    Sleep(1000);
}

int main(void) {
    XVideoSetMode(640, 480, 32, REFRESH_DEFAULT);

    while(1) {
        debugPrint("Hello nxdk!\n");
        Sleep(2000);
    }

    return 0;
}

This results in the final section, TEST, being generated with a physical section size greater than the virtual size.

The physical size is calculated here. The calculated physical size is 512 bytes in this case since the code section is filled with 0xCC.

Since this is the last section in the PE, the virtual size is pulled from the PE directly. here.

---

Calculating the physical size from the last zero-byte makes sense since the Xbox kernel will set the memory tail end of the section to zero based on the difference between physical and virtual size.

This PR attempts to fix this issue by ensuring the section's virtual size is at least as large as the physical size.

[thrimbor]

nit: The commit title prefix should be cxbe instead of cxbx

I think would be nice if we could lose some of the unnecessary `0xCC' in the file, but that's something we can think about in the future.
Code looks fine, I've left some comments about details.

[thrimbor]

I've never really noticed how weird and seemingly unnecessary this code is - unless it causes some breakage I'm not seeing rn we should imho just remove this part entirely.

[LoveMHz]

I wouldn't be opposed to making this a separate issue/pr.

In my opinion, there's a lot more of cxbe that should be simplified to trust the generated PE from the linker.

[thrimbor]

I always kind of assumed raw size > virtual size being fine because it's allowed in the PE format (SizeOfRawData is rounded to FileAlignment, VirtualSize is exact). Does it cause an issue in the XBE loader?

[LoveMHz]

It appears so. XepLoadSection takes in an XBE section and, after loading, attempts to clear the tail end of the section.

Retail 5838