Ensure that MurmurHash3_64.update handles ArrayBuffer input correctly, to avoid hash-collisions (issue 12533)

Different fonts incorrectly end up with *identical* hashes, despite having different /ToUnicode data.
The issue, and it's very interesting that we've apparently not seen it before, appears to be caused by the fact that different /ToUnicode entries share the *same* underlying `ArrayBuffer`, which thus becomes problematic at the `const dataUint32 = new Uint32Array(data.buffer, 0, blockCounts);` line. The simplest solution thus seem to be to just *copy* the input, when it's an `ArrayBuffer`, rather than using it as-is. (Note that if we'd stringified the input, when calling `MurmurHash3_64.update`, the issue would also have been fixed. In this case, we're already creating an unique TypedArray.)

src/core/murmurhash3.js

@@ -45,7 +45,7 @@ class MurmurHash3_64 {
         }
       }
     } else if (isArrayBuffer(input)) {
-      data = input;
+      data = input.slice();
       length = data.byteLength;
     } else {
       throw new Error(

test/pdfs/issue12533.pdf.link

@@ -0,0 +1 @@
+https://web.archive.org/web/20201026152003/https://www.mass.gov/doc/covid-19-dashboard-october-25-2020/download

test/test_manifest.json

@@ -2898,6 +2898,15 @@
        "link": false,
        "type": "eq"
     },
+    {  "id": "issue12533",
+       "file": "pdfs/issue12533.pdf",
+       "md5": "9824904320f884eee20d4e4573008e6f",
+       "rounds": 1,
+       "link": true,
+       "firstPage": 17,
+       "lastPage": 18,
+       "type": "eq"
+    },
     {  "id": "issue1466",
       "file": "pdfs/issue1466.pdf",
       "md5": "8a8877432e5bb10cfd50d60488d947bb",