RFR: JDK-8284037: Snippet-files subdirectory not automatically detected when in unnamed package [v2]

[Jonathan Gibbons]

> Please review a small fix to address use of snippets in source code in the unnamed package.
> 
> The core of the fix is to replace `packageName(pkg, utils)` (which returns `"<Unnamed>"` for the unnamed package) with plain old `pkg.getQualifiedName().toString()` (which returns an empty string for the unnamed package.)
> 
> There's some minor localized cleanup and rearrangement as well.
> 
> The test verifies behavior without and then with a source path, since that is the likely path of discovery by a user playing with the unnamed package.

Jonathan Gibbons has updated the pull request incrementally with one additional commit since the last revision:

  address review feedback

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/8708/files
  - new: https://git.openjdk.java.net/jdk/pull/8708/files/125474be..ccfb80b7

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=8708&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=8708&range=00-01

  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8708.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8708/head:pull/8708

PR: https://git.openjdk.java.net/jdk/pull/8708