A simpler, smaller and faster implementation of String.replace

[vjay82]

As discussed in #10178

[niloc132]

Something funny is happening in the tests for this change, I'm suspicious that this actually changes behavior in some fundamental way:

...
    [junit] Tests run: 128, Failures: 0, Errors: 113, Skipped: 0, Time elapsed: 1,240.88 sec
    [junit] Test com.google.gwt.core.CoreSuite FAILED
    [junit] Running com.google.gwt.core.ext.LinkerSuite
    [junit] Tests run: 29, Failures: 0, Errors: 10, Skipped: 0, Time elapsed: 1,223.858 sec
    [junit] Test com.google.gwt.core.ext.LinkerSuite FAILED
    [junit] Running com.google.gwt.debug.DebugSuite
    [junit] Tests run: 2, Failures: 0, Errors: 1, Skipped: 0, Time elapsed: 1,221.307 sec
    [junit] Test com.google.gwt.debug.DebugSuite FAILED
...

These suites don't usually take 20+ minutes to run. It doesn't seem to be a fluke, I re-ran them and they still timed out the build.

I'm not sure why this doesn't impact other runs - we're triggering the timeout for "this test isn't doing anything, kill it"

The browser did not complete the test method com.google.gwt.core.Core.JUnit:com.google.gwt.core.client.GWTTest.testCreate in 1200000ms.
  We have no results from:
127.0.0.1 / Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:94.0) Gecko/20100101 Firefox/94.0
Actual time elapsed: 1200.146 seconds.
Try increasing this timeout using the '-testMethodTimeout minutes' option

com.google.gwt.junit.client.TimeoutException: The browser did not complete the test method com.google.gwt.core.Core.JUnit:com.google.gwt.core.client.GWTTest.testCreate in 1200000ms.
  We have no results from:
127.0.0.1 / Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:94.0) Gecko/20100101 Firefox/94.0
Actual time elapsed: 1200.146 seconds.
Try increasing this timeout using the '-testMethodTimeout minutes' option

There is an error from htmlunit, it looks like our htmlunit build is too old to reliably use replaceAll:

TypeError: Cannot find function replaceAll in object com.google.gwt.core.Core.JUnit/junit.html. (script in about:blank from (-1, -1) to (-1, -1)#1)

replaceAll is relatively new, standard as of 2020 https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/replaceAll#browser_compatibility - our release of htmlunit is missing this, so we might need to back-burner this until we're ready for an htmlunit version bump (like #10113). In theory, we could do that while staying on ant with #10115, or wait until we're away from ant, and then just bump to a new release.

[zbynek]

Minimal version of HtmlUnit for this is 3.11.0 HtmlUnit/htmlunit-rhino-fork@3f5f6cc