Optimize toolchain regression test for VE by removing not a useful test
(-fuse-init-array test) and merge several tests to one test which checks
default behavior of driver. Also add sysroot to reduce conflicts.
These are suggested in https://reviews.llvm.org/D92996.
Thank you so much.
You probably should add an empty file in basic_ve_tree so that users who don't have a system ve toolchain (most upstream developers) have "...basic_ve_tree/...crtbegin.o" instead of "crtbegin.o"