Coallesce origin hit filters into their own bucket

Performance-related work.

There is a fair number of filters which can't be tokenized
in uBO's own filter lists. Majority of those filters also
declare a `domain=` option, examples:

    *$script,redirect-rule=noopjs,domain=...
    *$script,3p,domain=...,denyallow=...
    *$frame,3p,domain=...

Such filters can be found in uBO's asset viewer using the
following search expression:

    /^\*?\$[^\n]*?domain=/

Some filter buckets will contain many of those filters, for
instance one of the bucket holding untokenizable `redirect=`
filters has over 170 entries, which must be all visited when
collating all matching `redirect=` filters.

When a bucket contains many such filters, I found that it's
worth to extract all the non-negated hostname values from
`domain=` options into a single hntrie and perform a pre-test
at match() time to find out whether the current origin of a
network request matches any one of the collected hostnames,
so as to avoid iterating through all the filters.

Since there is rarely a match() for vast majority of network
requests with `domain=` option, this pre-test saves a good
amount of work, and this is measurable with the built-in
benchmark.

Author: gorhill

src/js/background.js

@@ -139,8 +139,8 @@ const µBlock = (( ) => { // jshint ignore:line
 
         // Read-only
         systemSettings: {
-            compiledMagic: 31,  // Increase when compiled format changes
-            selfieMagic: 31,    // Increase when selfie format changes
+            compiledMagic: 32,  // Increase when compiled format changes
+            selfieMagic: 32,    // Increase when selfie format changes
         },
 
         // https://github.com/uBlockOrigin/uBlock-issues/issues/759#issuecomment-546654501