Clean LOCAL_RESOURCE_DIR paths

With LOCAL_USE_AAPT2, resource directories like a/b/../res cause
problems, since ninja will canonicalize the path before creating the
intermediate resource directory, so it creates <intermediates>/a/res
while we give AAPT2 <intermediates>/a/b/../res, which fails to open.

Bug: 37716307
Test: Switch LOCAL_USE_AAPT2:=true for TelecommUnitTests, mma
Test: lunch aosp_marlin-userdebug; m -j
Change-Id: Id0d167e68185a119390e7b7e3c344895e77ca0e3