Fix 4848

[partouf]

Aiming to fix compiler-explorer/compiler-explorer#4848

Issue is: function starts with library file

Discussed before elsewhere, but to really fix this we must:

• Move the library filter to a post-process step
• Only eliminate the function that has no usercode at all, otherwise leave it

[OfekShilon]

Not sure what the fix was supposed to do. The problem (the rdtsc drop) persists even when checking off the library filter.

[partouf]

• Only eliminate the function that has no usercode at all, otherwise leave it

Correct, but the part that wasn't implemented here was the 2nd bulletpoint Only eliminate the function that has no usercode at all, otherwise leave it

[partouf]

(And it had a bug where libcode was sometimes always filtered it without looking at the filter setting)

[partouf]

But am extremely fuzzy on the details, i shouldve continued this pr when i understood what was going on