RFR: JDK-8304539: Cleanup utilities/{count_leading_zeros, count_trailing_zeros, population_count}.hpp [v10]

[Justin King]

> As the title says, cleanup the mentioned headers. This is similar to `byteswap.hpp` and removes the extraneous `#ifdef` for XLC since it is really just Clang now.

Justin King has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 14 commits:

 - Update Visual Studio to be 17.1
   
   Signed-off-by: Justin King <jcking at google.com>
 - Merge remote-tracking branch 'upstream/master' into popcount
 - Move template declaration
   
   Signed-off-by: Justin King <jcking at google.com>
 - Add default template implementation
   
   Signed-off-by: Justin King <jcking at google.com>
 - Add missing #endif
   
   Signed-off-by: Justin King <jcking at google.com>
 - Go back to templating for count_trailing_zeros for consistency
   
   Signed-off-by: Justin King <jcking at google.com>
 - Remove intrinsic specifier for CountOneBits
   
   Signed-off-by: Justin King <jcking at google.com>
 - Redo non-templated approach
   
   Signed-off-by: Justin King <jcking at google.com>
 - Remove unnecessary templating from count_trailing_zeros
   
   Signed-off-by: Justin King <jcking at google.com>
 - Fix ambiguous call
   
   Signed-off-by: Justin King <jcking at google.com>
 - ... and 4 more: https://git.openjdk.org/jdk/compare/97649489...1bc46ffa

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Changes: https://git.openjdk.org/jdk/pull/13103/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=13103&range=09
  Stats: 434 lines in 4 files changed: 203 ins; 151 del; 80 mod
  Patch: https://git.openjdk.org/jdk/pull/13103.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13103/head:pull/13103

PR: https://git.openjdk.org/jdk/pull/13103