installer: Refine the WoW64 decision logic

The registry and file reflection is also present on ARM64 platform.
Therefore, the reflection logic should resemble ${RunningX64} ||
${RunningX86} or `${IsWow64}` for short.

Signed-off-by: Simon Rozman <simon@rozman.si>

Author: rozmansi

installer/tap-windows6.nsi

@@ -202,7 +202,7 @@ ${EndIf}
 	!insertmacro MULTIUSER_INIT
 	SetShellVarContext all
 
-	${If} ${RunningX64}
+	${If} ${IsWow64}
 		SetRegView 64
 		StrCpy $INSTDIR "$PROGRAMFILES64\${PRODUCT_NAME}"
 	${Else}
@@ -315,7 +315,7 @@ Function un.onInit
 	ClearErrors
 	!insertmacro MULTIUSER_UNINIT
 	SetShellVarContext all
-	${If} ${RunningX64}
+	${If} ${IsWow64}
 		SetRegView 64
 	${EndIf}
 FunctionEnd