community/valhalla: unvendor gtest
currently we have two gtest versions in aports, one provided by valhalla:
$ apk info --provides valhalla
valhalla-3.1.4-r11 provides:
so:libgmock.so.1.11.0=1.11.0
so:libgmock_main.so.1.11.0=1.11.0
so:libgtest.so.1.11.0=1.11.0
so:libgtest_main.so.1.11.0=1.11.0
so:libvalhalla.so.3=3.1.4
cmd:valhalla_build_config=3.1.4-r11
cmd:valhalla_build_elevation=3.1.4-r11
cmd:valhalla_build_timezones=3.1.4-r11
cmd:valhalla_build_transit=3.1.4-r11