fix: skip empty functions, relax jump-threading to handle multi-instr jmp stubs

tests/example1.exe.cfg

@@ -1,5 +1,5 @@
 {
-  "binary": "tests\\example1.exe",
+  "binary": "C:\\Dev\\Current\\BinaryHardening\\cfgrip\\tests\\example1.exe",
   "mode": "full",
   "arch": "x86-64",
   "format": "PE",
@@ -82571,12 +82571,6 @@
         }
       ]
     },
-    {
-      "address": "0x14000c9d0",
-      "name": "",
-      "blocks": [
-      ]
-    },
     {
       "address": "0x140006544",
       "name": "",
@@ -95917,18 +95911,6 @@
         }
       ]
     },
-    {
-      "address": "0x140015200",
-      "name": "",
-      "blocks": [
-      ]
-    },
-    {
-      "address": "0x140011b00",
-      "name": "",
-      "blocks": [
-      ]
-    },
     {
       "address": "0x140012358",
       "name": "",
@@ -114576,18 +114558,6 @@
         }
       ]
     },
-    {
-      "address": "0x14000b204",
-      "name": "",
-      "blocks": [
-      ]
-    },
-    {
-      "address": "0x14000ca74",
-      "name": "",
-      "blocks": [
-      ]
-    },
     {
       "address": "0x14000a73c",
       "name": "",
@@ -135887,12 +135857,6 @@
         }
       ]
     },
-    {
-      "address": "0x1400075e8",
-      "name": "",
-      "blocks": [
-      ]
-    },
     {
       "address": "0x140009dc4",
       "name": "",
@@ -144893,12 +144857,6 @@
         }
       ]
     },
-    {
-      "address": "0x140007650",
-      "name": "",
-      "blocks": [
-      ]
-    },
     {
       "address": "0x140009f50",
       "name": "",
@@ -147615,12 +147573,6 @@
         }
       ]
     },
-    {
-      "address": "0x140004538",
-      "name": "",
-      "blocks": [
-      ]
-    },
     {
       "address": "0x14001a95c",
       "name": "",