fixup! Add logic to track rendering area of various PDF ops

Fix knownPartialMismatch markings

Author: nicolo-ribaudo

test/test_manifest.json

@@ -149,8 +149,7 @@
       "maxX": 0.5,
       "minY": 0.25,
       "maxY": 0.5
-    },
-    "_knownPartialMismatch": true
+    }
   },
   {
     "id": "issue16432",
@@ -765,8 +764,7 @@
       "minY": 0.25,
       "maxY": 0.5
     },
-    "_": "Two one-bit differences at the bottom edge of page 22",
-    "knownPartialMismatch": true
+    "knownPartialMismatch": "Two one-bit differences at the bottom edge of page 22"
   },
   {
     "id": "intelisa-84-partial",
@@ -782,7 +780,8 @@
       "maxX": 0.5,
       "minY": 0.25,
       "maxY": 0.5
-    }
+    },
+    "knownPartialMismatch": "Gives slightly different results in Firefox when running in headless mode"
   },
   {
     "id": "issue2128",
@@ -1256,8 +1255,7 @@
       "minY": 0.25,
       "maxY": 0.5
     },
-    "_": "TODO: I cannot figure out what the mismatch is. 'Circle differences' circles something, but then with the 'big pixels' view there are no differences.",
-    "knownPartialMismatch": true
+    "knownPartialMismatch": "TODO: I cannot figure out what the mismatch is. 'Circle differences' circles something, but then with the 'big pixels' view there are no differences."
   },
   {
     "id": "issue3371",
@@ -1352,8 +1350,7 @@
       "minY": 0.25,
       "maxY": 0.5
     },
-    "_": "Two one-bit differences at the bottom edge of page 11",
-    "knownPartialMismatch": true
+    "knownPartialMismatch": "Two one-bit differences at the bottom edge of page 11"
   },
   {
     "id": "issue6769_no_matrix",
@@ -1383,8 +1380,7 @@
       "minY": 0.25,
       "maxY": 0.5
     },
-    "_": "A one-bit difference at the bottom edge of page 29",
-    "knownPartialMismatch": true
+    "knownPartialMismatch": "A one-bit difference at the bottom edge of page 29"
   },
   {
     "id": "issue4909",
@@ -1560,7 +1556,8 @@
       "maxX": 0.5,
       "minY": 0.25,
       "maxY": 0.5
-    }
+    },
+    "knownPartialMismatch": "Gives slightly different results in Firefox when running in headless mode"
   },
   {
     "id": "bug1811668",
@@ -5843,8 +5840,7 @@
       "minY": 0.25,
       "maxY": 0.5
     },
-    "_": "Slightly different (not visible) partial pixel color at the edge of the image",
-    "knownPartialMismatch": true
+    "knownPartialMismatch": "Slightly different (not visible) partial pixel color at the edge of the image"
   },
   {
     "id": "bug1064894",
@@ -6358,8 +6354,7 @@
       "minY": 0.25,
       "maxY": 0.5
     },
-    "_": "Slightly different (not visible) single pixel color at the edge of the image",
-    "knownPartialMismatch": true
+    "knownPartialMismatch": "Slightly different (not visible) single pixel color at the edge of the image"
   },
   {
     "id": "issue4890",
@@ -8085,8 +8080,7 @@
       "minY": 0.25,
       "maxY": 0.5
     },
-    "_": "Half pixel rendering at the edge of the image",
-    "knownPartialMismatch": true
+    "knownPartialMismatch": "Half pixel rendering at the edge of the image"
   },
   {
     "id": "issue16454",