Fix Inefficient Regular Expression for setZoomMode

[yetingli]

Fix Inefficient Regular Expression for setZoomMode

Add test case for setZoomMode

[HackbrettXXX]

The new test case fails:

FAILED TESTS:
  Core: Unit Tests
    ✖ jsPDF private function setZoomMode, getZoomMode
      IE 11.0 (Windows 10)
      Chrome 94.0.4606.54 (Windows 10)
      Firefox 77.0 (Windows 10)
    Expected function to throw an exception.
    <Jasmine>
    @test/specs/jspdf.unit.spec.js:799:8
    <Jasmine>

[yetingli]

The new test case fails:

FAILED TESTS:
  Core: Unit Tests
    ✖ jsPDF private function setZoomMode, getZoomMode
      IE 11.0 (Windows 10)
      Chrome 94.0.4606.54 (Windows 10)
      Firefox 77.0 (Windows 10)
    Expected function to throw an exception.
    <Jasmine>
    @test/specs/jspdf.unit.spec.js:799:8
    <Jasmine>

Thanks a lot! Can I delete the new test case directly?

[HackbrettXXX]

Yes, deleting the test case is OK.

[yetingli]

Please see #3368. Thanks a lot!