Ignore register unwinder callback for empty patch_info data table on Windows. (#33726)

Ignore register unwinder callback for empty patch_info data table on Windows. (#33726)

Running System.Runtime.Serialization.Xml test suite triggers calls to
mono_code_manager_reserve with 0 size code block. On Windows, allocating
code regions from code manager will also add callback for code region
into unwinder function table, but since region could be 0 length,
it will be causing a crash in RtlInstallFunctionTableCallback OS call.

Fix hardens code to not try to register callbacks for code regions
of size 0, since that is considered a critical error by Windows OS API.