Revert "ExternalProject: Add TEST_EXCLUDE_FROM_MAIN option"

This reverts commit 0bdf24548b2059d9e11520f2de492b4847aefb8f.
It will be revised and restored.
Merge topic 'ExternalProject_TEST_EXCLUDE_FROM_MAIN' into next

bf94493b Revert "ExternalProject: Add TEST_EXCLUDE_FROM_MAIN option"
Merge topic 'doc-mixed-case-commands'

607b39dc Utilities/Sphinx: Fix link targets for mixed-case command names
Merge branch 'master' into next
Merge topic 'vs-hlsl-typo'

955fbf29 VS: Fix typo in VS_SHADER_MODEL lookup comment
Merge topic 'fix-add_library-check-for-shared'

bd360ee3 add_library: Fix target type check for non-shared-lib platforms
Merge topic 'cached-regex-clear-fixed'

ceecd790 cmMakefile: store the number of last matches in a CMake var
7878d061 test: add a test for clearing regex results
Merge topic 'FindUnixCommands-use-FPHSA'

ff50046b FindUnixCommand: Use FPHSA to report status in standard way
Merge branch 'master' into next