YJIT: Fix edge and total counts in exit_locations (#7702)

The stackprof-format raw samples are suffixed with a count (ie. how many
times did the previously recorded side-exit repeat). Previously we were
correctly using this value to increment the :samples count, but not the
:total_samples count or edges.

This made the stackprof aggregate results incorrect (though any
flamegraphs generated should have been correct, since those only rely on
raw samples).

yjit.rb

@@ -70,6 +70,8 @@ def self.exit_locations
       stack_length = raw_samples[i] + 1
       i += 1 # consume the stack length
 
+      sample_count = raw_samples[i + stack_length]
+
       prev_frame_id = nil
       stack_length.times do |idx|
         idx += i
@@ -78,14 +80,14 @@ def self.exit_locations
         if prev_frame_id
           prev_frame = frames[prev_frame_id]
           prev_frame[:edges][frame_id] ||= 0
-          prev_frame[:edges][frame_id] += 1
+          prev_frame[:edges][frame_id] += sample_count
         end
 
         frame_info = frames[frame_id]
-        frame_info[:total_samples] += 1
+        frame_info[:total_samples] += sample_count
 
         frame_info[:lines][line_samples[idx]] ||= [0, 0]
-        frame_info[:lines][line_samples[idx]][0] += 1
+        frame_info[:lines][line_samples[idx]][0] += sample_count
 
         prev_frame_id = frame_id
       end
@@ -95,8 +97,6 @@ def self.exit_locations
       top_frame_id = prev_frame_id
       top_frame_line = 1
 
-      sample_count = raw_samples[i]
-
       frames[top_frame_id][:samples] += sample_count
       frames[top_frame_id][:lines] ||= {}
       frames[top_frame_id][:lines][top_frame_line] ||= [0, 0]