tomcat-native: add option to use homebrew's APR

Yosemite ships with APR 1.4.8. This new option
allows using newer versions (eg. 1.5.1) from the
homebrew/apache tap.

Closes #33805.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
TapDependency: add tap accessor.
test-bot: tap TapDependency's tap.