Sync ruby/ruby#14866

Low resolution-clock is added in windows, but it shouldn't be used in assert_linear_performance.
ruby/ruby's core_assertion.rb selects clock that has enough resolution.

Author: tompng

lib/core_assertions.rb

@@ -835,6 +835,9 @@ def assert_all_assertions_foreach(msg = nil, *keys, &block)
             rescue
               # Constants may be defined but not implemented, e.g., mingw.
             else
+              unless Process.clock_getres(clk) < 1.0e-03
+                next # needs msec precision
+              end
               PERFORMANCE_CLOCK = clk
             end
           end