Test for dragging operations of <input type=range> when readonly or disabled are toggled.

Tests for range dragging while it toggles to be readonly.
readOnly=false, disabled=false
PASS input.value is "100"
PASS changeEventCounter is >= lastChangeEventCounter + 1
PASS input.value is "0"
PASS changeEventCounter is >= lastChangeEventCounter + 1
readOnly=true
PASS input.value is "0"
PASS lastChangeEventCounter is changeEventCounter

Tests for range dragging while it toggles to be disabled.
readOnly=false, disabled=false
PASS input.value is "100"
PASS changeEventCounter is >= lastChangeEventCounter + 1
PASS input.value is "0"
PASS changeEventCounter is >= lastChangeEventCounter + 1
disabled=true
PASS input.value is "0"
PASS lastChangeEventCounter is changeEventCounter

PASS successfullyParsed is true

TEST COMPLETE