RFR: 8295663 Rephrased introduction to testing [v2]

[Ludvig Janiuk]

> Old one made little sense for a new reader

Ludvig Janiuk has updated the pull request incrementally with one additional commit since the last revision:

  reflow

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Changes:
  - all: https://git.openjdk.org/jdk/pull/10763/files
  - new: https://git.openjdk.org/jdk/pull/10763/files/34142667..e80d40e0

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=10763&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=10763&range=00-01

  Stats: 67 lines in 2 files changed: 11 ins; 0 del; 56 mod
  Patch: https://git.openjdk.org/jdk/pull/10763.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10763/head:pull/10763

PR: https://git.openjdk.org/jdk/pull/10763