RFR: JDK-8300260: Remove metaprogramming/isSame.hpp [v2]

[Justin King]

> Code cleanup of pre-C++11 <type_traits> implementations.

Justin King has updated the pull request incrementally with one additional commit since the last revision:

  Revert back from std::is_void to std::is_same
  
  Signed-off-by: Justin King <jcking at google.com>

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Changes:
  - all: https://git.openjdk.org/jdk/pull/12040/files
  - new: https://git.openjdk.org/jdk/pull/12040/files/827f8d81..19a991ad

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=12040&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=12040&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/12040.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12040/head:pull/12040

PR: https://git.openjdk.org/jdk/pull/12040