[jdk11u-dev] RFR: 8325972: Add -x to bash for building with LOG=debug

[Andrew Lu]

I backport this for parity with 11.0.24-oracle.

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Commit messages:
 - Backport 8668198c26bdac412f0a9d1255ca74da860761c5

Changes: https://git.openjdk.org/jdk11u-dev/pull/2579/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk11u-dev&pr=2579&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8325972
  Stats: 5 lines in 1 file changed: 4 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk11u-dev/pull/2579.diff
  Fetch: git fetch https://git.openjdk.org/jdk11u-dev.git pull/2579/head:pull/2579

PR: https://git.openjdk.org/jdk11u-dev/pull/2579