Revert "[Fix]"[-Wunsafe-buffer-usage] Add a new `forEachDescendant` matcher...

Revert "[Fix]"[-Wunsafe-buffer-usage] Add a new `forEachDescendant` matcher that skips callable declarations""

This reverts commit ef47a0a7.

Revert "[-Wunsafe-buffer-usage] Add a new `forEachDescendant` matcher that skips callable declarations"

This reverts commit b2ac5fd7.

This patch is causing failure in some Sanitizer tests
(https://lab.llvm.org/buildbot/#/builders/5/builds/30522/steps/13/logs/stdio).  Reverting the patch and its' fix.