[jdk17u-dev] RFR: 8304134: jib bootstrapper fails to quote filename when checking download filetype

[Goetz Lindenmaier]

I backport this for parity with 17.0.8-oracle.

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Commit messages:
 - Backport 75168eaca3f665785519bb489073962a4972fdc0

Changes: https://git.openjdk.org/jdk17u-dev/pull/1265/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=1265&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8304134
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/1265.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/1265/head:pull/1265

PR: https://git.openjdk.org/jdk17u-dev/pull/1265