fix tidb-debug docker build (#2215)

[sre-bot]

cherry-pick #2215 to release-1.1

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What problem does this PR solve?

# wget http://download.pingcap.org/tidb-latest-linux-amd64.tar.gz
...
# tar -xvf tidb-latest-linux-amd64.tar.gz 
tidb-v3.0.12-linux-amd64/
tidb-v3.0.12-linux-amd64/bin/
tidb-v3.0.12-linux-amd64/bin/pd-server
tidb-v3.0.12-linux-amd64/bin/tidb-ctl
tidb-v3.0.12-linux-amd64/bin/reparo
tidb-v3.0.12-linux-amd64/bin/tikv-ctl
tidb-v3.0.12-linux-amd64/bin/drainer
tidb-v3.0.12-linux-amd64/bin/binlogctl
tidb-v3.0.12-linux-amd64/bin/arbiter
tidb-v3.0.12-linux-amd64/bin/etcdctl
tidb-v3.0.12-linux-amd64/bin/pd-ctl
tidb-v3.0.12-linux-amd64/bin/tikv-server
tidb-v3.0.12-linux-amd64/bin/tidb-server
tidb-v3.0.12-linux-amd64/bin/pd-recover
tidb-v3.0.12-linux-amd64/bin/pump

What is changed and how does it work?

Check List

Tests

• Unit test
• E2E test
• Stability test
• Manual test (add detailed scripts or steps below)
• No code

Code changes

• Has Go code change
• Has CI related scripts change
• Has Terraform scripts change

Side effects

• Breaking backward compatibility

Related changes

• Need to cherry-pick to the release branch
• Need to update the documentation

Does this PR introduce a user-facing change?:

NONE

[cofyc]

/merge

[sre-bot]

/run-all-tests

[sre-bot]

@sre-bot merge failed.