How to fix high kernel_task on sierra?
The path: /System/Library/Extensions/IOPlatformPluginFamily.kext/Contents/PlugIns/ACPI_SMC_PlatformPlugin.kext/Contents/Resources" is still existing and it indeed contains a lot of plists with Mac identifier names (e.g. MacBookPro8_1.plist). The whole path starting with /System is protected by SIP though. To modify (i.e. move) files here you have to disable SIP.



I strongly recommend to leave the plist where it is and search for the real culprit. In your linked example it's not really the kernel_task but the AirMail process which bogs the CPU. One solution is then to disable/modify Airmail. 

Since you didn't add an Activity Monitor screenshot I don't know the real reason why your CPU is forced to its knees.