Fix #22813 - Removing __monitor from Object leads to errors

[dkorpel]

Closes #22813

Need to check whether LDC and GDC use target.classinfosize

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[thewilsonator]

LDC does not.

[thewilsonator]

GDC appears not to: https://github.com/search?q=repo%3AD-Programming-GDC%2Fgcc%20classinfosize&type=code

[thewilsonator]

Need to update compilable/b18242.d

// REQUIRED_ARGS: -c
// PERMUTE_ARGS:
module object;

class Object { }

class TypeInfo { }
class TypeInfo_Class : TypeInfo
{
    version(D_LP64) { ubyte[136+24] _x; } else { ubyte[68+20] _x; }
}

class Throwable { }

int _d_run_main()
{
    try { } catch(Throwable e) { return 1; }
    return 0;
}

(why that compilable test defines _d_run_main when it has // REQUIRED_ARGS: -c I'm not sure, but the size calculations for the size of TypeInfo_Class need updating)

Looking good!

[thewilsonator]

Ping. Fixed the test, is this good to go now?

[dkorpel]

Yes, thanks