bpo-42825: Enable /OPT:REF (GH-24098)

We explicitly disable /OPT:ICF as some manual optimisations depend on some functions still having distinct pointers (such as wrap_binary_func and wrap_binary_func_l).

PCbuild/pyproject.props

@@ -74,6 +74,7 @@
       <LinkTimeCodeGeneration Condition="$(SupportPGO) and $(Configuration) == 'PGInstrument'">PGInstrument</LinkTimeCodeGeneration>
       <LinkTimeCodeGeneration Condition="$(SupportPGO) and $(Configuration) == 'PGUpdate'">PGUpdate</LinkTimeCodeGeneration>
       <AdditionalDependencies>advapi32.lib;shell32.lib;ole32.lib;oleaut32.lib;%(AdditionalDependencies)</AdditionalDependencies>
+      <AdditionalOptions Condition="$(Configuration) != 'Debug'">/OPT:REF,NOICF %(AdditionalOptions)</AdditionalOptions>
     </Link>
     <Lib>
       <LinkTimeCodeGeneration Condition="$(Configuration) == 'Release'">true</LinkTimeCodeGeneration>