TAS: fix conflict between pocl AS numbers and final AS numbers
TAS: fix conflict between pocl AS numbers and final AS numbers

Some of the pocl AS numbers were the same as the final device AS numbers,
causing issues when TAS conversion code converted more than once (like
with global variables referenced later by functions). Caused problems
for both HSA and TCE.

This fixes it for both by first converting the pocl AS to high numbers,
then mapping those to actual device AS.

rjodin/pocl,vkorhonen/pocl,pocl/pocl,jrprice/pocl,pocl/pocl,dsandersimgtec/pocl,jrprice/pocl,franz/pocl,pocl/pocl,vkorhonen/pocl,pocl/pocl,Oblomov/pocl,Oblomov/pocl,franz/pocl,vkorhonen/pocl,pavanky/pocl,pavanky/pocl,franz/pocl,pocl/pocl,franz/pocl,pavanky/pocl,dsandersimgtec/pocl,rjodin/pocl,dsandersimgtec/pocl,rjodin/pocl,Oblomov/pocl,rjodin/pocl,vkorhonen/pocl,Oblomov/pocl,jrprice/pocl,pavanky/pocl,Oblomov/pocl,franz/pocl,jrprice/pocl,dsandersimgtec/pocl