Add clang wrapper to log compiler errors.

Use --redirect-stderr to redirect all stderr emitted by clang.

Test: python test_compiler.py ../../.. --build-only  --target
aosp_angler-user and check clang-error.log in $OUT.
Bug: http://b/62292583

Change-Id: Ifd7f48d19421f6918b47ea8826fa67afcc6daa54
4 files changed