Allow host self-references in external/icu/...

I'm adding macOS universal binary support to Soong, so that most
host darwin binaries will have two variants, x86_64 and arm64. One of
them will depend on the other in order to combine them into a universal
binary, but that triggers this dependency check.

Bug: 203607969
Test: m sdk-repo-build-tools sdk-repo-platform-tools on Mac
Change-Id: I3a355b156be4774f8e618ef9b0ba76a6fb43b5b6
1 file changed