RFR: 8283013: Simplify Arguments::parse_argument()

[Ioi Lam]

- Remove all the complex `sscanf()` calls in `Arguments::parse_argument()`
- Call the appropriate parsing function according to the type of the flag
- Added more test cases for flags of the `double` type.

As a result of this change, `double` flags can now be specified in more ways, as long as the input is accepted by `strtod()`. However, `NaN` and `INFINITY` values are not allowed because the VM probably cannot handle them. Please see the test case for details.

Tested with tiers 1-5.

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Commit messages:
 - Merge branch 'master' of https://github.com/openjdk/jdk into 8283013-simplify-parse-argument
 - disallow NAN and INF
 - 8283013: Simplify Arguments::parse_argument()

Changes: https://git.openjdk.java.net/jdk/pull/7916/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=7916&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8283013
  Stats: 210 lines in 3 files changed: 96 ins; 73 del; 41 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7916.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7916/head:pull/7916

PR: https://git.openjdk.java.net/jdk/pull/7916