Skip problematic Process.clock_getres specs on ARM

* https://rubyci.org/logs/rubyci.s3.amazonaws.com/scw-9d6766/ruby-trunk/log/20190428T051708Z.fail.html.gz
* https://rubyci.org/logs/rubyci.s3.amazonaws.com/scw-ad7f67/ruby-trunk/log/20190428T045405Z.fail.html.gz

spec/ruby/core/process/clock_getres_spec.rb

@@ -3,7 +3,7 @@ require_relative 'fixtures/clocks'
 
 describe "Process.clock_getres" do
   platform_is_not :freebsd do # clock_getres() seems incorrect on FreeBSD
-    ProcessSpecs.clock_constants.each do |name, value|
+    ProcessSpecs.clock_constants_for_resolution_checks.each do |name, value|
       it "matches the clock in practice for Process::#{name}" do
         times = []
         10_000.times do

spec/ruby/core/process/fixtures/clocks.rb

@@ -9,14 +9,28 @@ module ProcessSpecs
       # Process#clock_gettime. They return EINVAL if the permission
       # is not granted.
       clocks -= [:CLOCK_BOOTTIME_ALARM, :CLOCK_REALTIME_ALARM]
-
-      # These clocks in practice on Linux do not seem to match
-      # their reported resolution.
-      clocks -= [:CLOCK_REALTIME_COARSE, :CLOCK_MONOTONIC_COARSE]
     end
 
     clocks.map { |c|
       [c, Process.const_get(c)]
     }
   end
+
+  def self.clock_constants_for_resolution_checks
+    clocks = clock_constants
+
+    # These clocks in practice on Linux do not seem to match their reported resolution.
+    clocks = clocks.reject { |clock, value|
+      [:CLOCK_REALTIME_COARSE, :CLOCK_MONOTONIC_COARSE].include?(clock)
+    }
+
+    # These clocks in practice on ARM on Linux do not seem to match their reported resolution.
+    platform_is :armv7l, :aarch64 do
+      clocks = clocks.reject { |clock, value|
+        [:CLOCK_PROCESS_CPUTIME_ID, :CLOCK_THREAD_CPUTIME_ID, :CLOCK_MONOTONIC_RAW].include?(clock)
+      }
+    end
+
+    clocks
+  end
 end