zorg Xcode python test suite target arch update
zorg Xcode python test suite target arch update

This changes the Xcode target used by the Green Dragon Xcode CI.
When calling xcodebuild with LLDB_PYTHON_TESTSUITE_ARCH set, the
arch's xUnit XML output is now set to an arch-specific filename:

$(BUILD_DIR)/test-results-$(LLDB_PYTHON_TESTSUITE_ARCH).xml.

The change also ensures that the Python testsuite sees the Xcode
build settings passed in through environment variables.

git-svn-id: 4c4cc70b1ef44ba2b7963015e681894188cea27e@282605 91177308-0d34-0410-b5e6-96231b3b80d8

apple/swift-lldb,apple/swift-lldb,llvm-mirror/lldb,llvm-mirror/lldb,apple/swift-lldb,apple/swift-lldb,apple/swift-lldb,apple/swift-lldb,llvm-mirror/lldb,llvm-mirror/lldb,llvm-mirror/lldb