RFR: 8304956: Update KeyStore.getDefaultType​() specification to return pkcs12 as fallback [v3]

[Ben Perez]

> Replaced "jks" with "pkcs12" in both the spec and fallback for `KeyStore.getDefaultType()`

Ben Perez has updated the pull request incrementally with one additional commit since the last revision:

  Added test to check that when keystore.type is null it defaults to pkcs12

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Changes:
  - all: https://git.openjdk.org/jdk/pull/15625/files
  - new: https://git.openjdk.org/jdk/pull/15625/files/23c357be..26978443

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=15625&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=15625&range=01-02

  Stats: 56 lines in 2 files changed: 56 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/15625.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15625/head:pull/15625

PR: https://git.openjdk.org/jdk/pull/15625