Move CleanSpec.mk out of icu4c/ icu4j/ directory

CleanSpec.mk should work even though it's located out of icu4c/ directory.

We shouldn't add Android-specfic files into icu4c/ icu4j/ unless
it must be required, because the 2 directories come from upstream,
and we mimimize Android-specific files in the directory.

Test: m
Change-Id: Ic7146786b9353cf7c4d71df93c2c12b89cee8073
1 file changed