gdb, amd64: extend the amd64 prologue analyzer to skip stack alloc

gdb, amd64: extend the amd64 prologue analyzer to skip stack alloc

Following the previous patch (gdb, amd64: extend the amd64 prologue
analyzer to skip register pushes), this patch extends the analyzer
further to be able to skip stack space allocation as the next prologue
part, for functions with a frame pointer.  Implementation was based
on the i386 counterpart, which already had that functionality.

As of now, the stack allocation is not skipped.  Examples below use C
source listed below, compiled with gcc 11.4.0.
```
	int foo (int n)
	{
	    int ns[] = { 1, 4, 9, 16, 25 };
	    return ns[n];
	}

	int
	main (int argc, char **argv)
	{
	    return foo (argc);
	}
```

Compiling with "gcc -O0 -fno-omit-frame-pointer" we get:
```
	(gdb) b foo
	Breakpoint 1 at 0x1151
	(gdb) r
	...
	Breakpoint 1, 0x0000555555555151 in foo ()
	(gdb) disassemble
	Dump of assembler code for function foo:
	   0x0000555555555149 <+0>:     endbr64
	   0x000055555555514d <+4>:     push   %rbp
	   0x000055555555514e <+5>:     mov    %rsp,%rbp
	=> 0x0000555555555151 <+8>:     sub    $0x30,%rsp
	   0x0000555555555155 <+12>:    mov    %edi,-0x24(%rbp)
	...
```

With this patch, it gets skipped the same way register pushes are:
```
	(gdb) b foo
	Breakpoint 1 at 0x1155
	(gdb) r
	...
	Breakpoint 1, 0x0000555555555155 in foo ()
	(gdb) disassemble
	Dump of assembler code for function foo:
	   0x0000555555555149 <+0>:     endbr64
	   0x000055555555514d <+4>:     push   %rbp
	   0x000055555555514e <+5>:     mov    %rsp,%rbp
	   0x0000555555555151 <+8>:     sub    $0x30,%rsp
	=> 0x0000555555555155 <+12>:    mov    %edi,-0x24(%rbp)
	...
```

Reviewed-By: Guinevere Larsen <guinevere@redhat.com>
Approved-By: Andrew Burgess <aburgess@redhat.com>