Explicitly make building tzcode single threaded

make tzcode in ICU4C is not safe to be run using
multiple threads (i.e. -j{n}). This change explicitly
passes -j1 to the affected build step because it
had problems for developers who have set
MAKEFLAGS in their environment.

Upstream bug http://bugs.icu-project.org/trac/ticket/13821
has been created to try to have it addressed there.

The parallelism has also been made explicit in another
make invocation for completeness.

Bug: 109641429
Test: Ran update-tzdata.py (system/timezone) and updateicudata.py
Change-Id: I63d6c0dbcc1afd7e9e3991427db9a5305ebbec63
1 file changed