Remove build_old and rename build_new to build
Remove build_old and rename build_new to build

This PR bumps the required Go version to 1.19, so the old builds will
no longer work. Keep only 1.19 tests.

Signed-off-by: Dionna Glaze <afb12ac6972c28521d17bb015180bb1a97d1fc2c@google.com>

google/go-tpm-tools,google/go-tpm-tools,google/go-tpm-tools