cmSystemTools: Remove IsInternallyOn, IsNOTFOUND, IsOn, IsOff

The removes the following methods from cmSystemTools:

- `IsInternallyOn`
- `IsNOTFOUND`
- `IsOn`
- `IsOff`
36 jobs for cmStringAlgorithms_IsOn
Status Job ID Name Coverage
  External
passed cdash

passed cmake-dash3win10-windows-release-ninja

passed cmake-hythloth-linux-debug-makefiles+sphinx

passed cmake-minoc-linux-release-lint-iwyu-tidy

passed cmake-moonshade-osx-debug-ninja

passed cmake-moonshade-osx-release-makefiles

passed cmake-terfin-windows-release-vs2019

passed ghostflow-check-master

passed ghostflow-stager

passed cmake-dash3win10-windows-release-ninja

00:16:26

passed cmake-dash3win10-windows-release-ninja

passed cmake-hythloth-linux-debug-makefiles+sphinx

passed cmake-hythloth-linux-debug-makefiles+sphinx

00:51:38

passed cmake-minoc-linux-release-lint-iwyu-tidy

passed cmake-minoc-linux-release-lint-iwyu-tidy

00:01:34

passed cmake-moonshade-osx-debug-ninja

passed cmake-moonshade-osx-debug-ninja

00:09:22

passed cmake-moonshade-osx-release-makefiles

passed cmake-moonshade-osx-release-makefiles

00:10:10

passed cmake-terfin-windows-release-vs2019

00:37:14

passed cmake-terfin-windows-release-vs2019

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager