Revert "Parse the triple in base-config-ix to propagate ANDROID variable correctly"

This reverts commit r273914.

This commit broke bots building compiler-rt using LLVM_BUILD_EXTERNAL_COMPILER_RT. See:
http://lab.llvm.org:8080/green/job/clang-stage1-configure-RA_build/22221/console

llvm-svn: 273956