RFR: 8341666: FileInputStream doesn't support readAllBytes() or readNBytes(int) on pseudo devices [v5]

[Brian Burkhalter]

> Modify `FileInputStream` (FIS) to fall back to the superclass implementations of `readAllBytes()`, `readNBytes(int)`, `skip()`, and `transferTo` when the input source would otherwise fail with "Illegal Seek" in the FIS implementation, such as for the standard input or a named pipe.

Brian Burkhalter has updated the pull request incrementally with two additional commits since the last revision:

 - 8341666: Update comments of isRegularFile field and isRegularFile() method
 - 8341666: Fix typo in previous commit

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/21673/files
  - new: https://git.openjdk.org/jdk/pull/21673/files/e091f157..98f918a9

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=21673&range=04
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=21673&range=03-04

  Stats: 5 lines in 2 files changed: 0 ins; 1 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/21673.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21673/head:pull/21673

PR: https://git.openjdk.org/jdk/pull/21673