realtime_block: log timings to stderr on exception in outermost block

Not necessary in inner blocks as timing still gets stored in hash
and if caught will be returned from some outer block.
When outermost block crashes, the whole hash is about to be discarded.

lib/gems/pending/util/extensions/miq-benchmark.rb

@@ -34,6 +34,10 @@ def self.realtime_block(key, &block)
         begin
           ret = realtime_store(hash, key, &block)
           return ret, hash
+        rescue Exception
+          # Don't let timings be lost on exception when there is nobody else to pick them up.
+          Logger.new($stderr).info("Exception in realtime_block #{key.inspect} - Timings: #{hash.inspect}")
+          raise
         ensure
           delete_current_realtime
         end

spec/util/extensions/miq-benchmark_spec.rb

@@ -64,6 +64,43 @@
     expect(Benchmark.in_realtime_block?).to be_falsey
   end
 
+  it '.realtime_block with an Exception aborting outermost block' do
+    expect do
+      Benchmark.realtime_block(:test1) do
+        Timecop.travel(2.1)
+        Benchmark.realtime_block(:test2) do
+          Timecop.travel(5.1)
+          raise Exception
+        end
+      end
+    end.to raise_exception(Exception)
+       .and output(/Exception in realtime_block :test1 - Timings: {:test2=>5\.\d*, :test1=>7\.\d*}/).to_stderr
+
+    expect(Benchmark.in_realtime_block?).to be_falsey
+  end
+
+  it '.realtime_block with an Exception caught in inner block' do
+    result = timings = nil
+    expect do
+      result, timings = Benchmark.realtime_block(:test1) do
+        begin
+          Timecop.travel(500)
+          Benchmark.realtime_block(:test2) do
+            Timecop.travel(500)
+            raise Exception
+          end
+        rescue Exception
+          "value"
+        end
+      end
+    end.to_not output.to_stderr
+
+    expect(result).to eq("value")
+    expect(timings[:test1]).to be_within(0.5).of(1000)
+    expect(timings[:test2]).to be_within(0.5).of(500)
+    expect(Benchmark.in_realtime_block?).to be_falsey
+  end
+
   it "Timeout raising within .realtime_block" do
     expect(Benchmark.in_realtime_block?).to be_falsey