Set default pool when RBE or goma is enabled

Pass --default_pool=local_pool to kati when RBE or goma is enabled
to put most rules into the local_pool.  Specific rules that support
RBE or goma will set .KATI_NINJA_POOL := none to remove themselves
from the local_pool.  Passing --default_pool will also disable the
hack in kati that sets the pool based on the presence of the string
"/gomacc" in the command line.

Fixes: 143938974
Test: inspect pools in build-${TARGET-PRODUCT}.ninja for m USE_RBE=true
Test: inspect pools in build-${TARGET-PRODUCT}.ninja for m USE_GOMA=true
Change-Id: I839b2488383fcd63fffd613e25b0b9abcb72b567