Add array.reverse(array) and strings.reverse(string) built-in functions. (#4161)

The function `array.reverse` takes an array as an argument, and returns an array with a reversed order of elements.
The function `strings.reverse` takes a string as an argument, and returns a string with a reversed order of unicode code points.
WASM support is included for both built-ins.

Fixes #3736

Signed-off-by: Kristian Svalland <kristian.svalland@gmail.com>

capabilities.json

@@ -123,6 +123,26 @@
         "type": "function"
       }
     },
+    {
+      "name": "array.reverse",
+      "decl": {
+        "args": [
+          {
+            "dynamic": {
+              "type": "any"
+            },
+            "type": "array"
+          }
+        ],
+        "result": {
+          "dynamic": {
+            "type": "any"
+          },
+          "type": "array"
+        },
+        "type": "function"
+      }
+    },
     {
       "name": "array.slice",
       "decl": {
@@ -2979,6 +2999,20 @@
         "type": "function"
       }
     },
+    {
+      "name": "strings.reverse",
+      "decl": {
+        "args": [
+          {
+            "type": "string"
+          }
+        ],
+        "result": {
+          "type": "string"
+        },
+        "type": "function"
+      }
+    },
     {
       "name": "substring",
       "decl": {