RFR: 8256182: Update qemu-debootstrap cross-compilation recipe [v3]

[Aleksey Shipilev]

> Update the docs with the (f)actual recipe used in JDK-8256127.

Aleksey Shipilev has updated the pull request incrementally with one additional commit since the last revision:

  Properly indent the code blocks

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/1160/files
  - new: https://git.openjdk.java.net/jdk/pull/1160/files/187b2962..fcb48697

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=1160&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=1160&range=01-02

  Stats: 43 lines in 2 files changed: 1 ins; 7 del; 35 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1160.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1160/head:pull/1160

PR: https://git.openjdk.java.net/jdk/pull/1160