Changes

fix(cd): fix build-comon for tikv when given builder image (#3323)

This pull request includes a small change to the
`jenkins/pipelines/cd/atom-jobs/build-common.groovy` file. The change
modifies the condition for using GCC 8 on Linux systems by checking for
the existence of the file `/opt/rh/devtoolset-8/enable` instead of an
empty `BUILDER_IMG` variable.

Changes in `jenkins/pipelines/cd/atom-jobs/build-common.groovy`:

* Modified the condition to check for the existence of the file
`/opt/rh/devtoolset-8/enable` to enable GCC 8 on Linux systems.

Signed-off-by: wuhuizuo <wuhuizuo@126.com>
 (commit: 11e2c3a)