Add a test for PR 13490

The bug itself was already fixed by Eric Dobson
Make static single flonum checks correct.

Closes PR13499.
Add extra tests and warning about -PosIntNotFixnum.
adjust test cases for recent changes to the lexers
New Racket version 5.3.3.1.
Supporting headers and stateless in web-server/test
Fix :print-type. Closes PR13503.
Make overlap more precise.
Add missing pure functions.
For/product treated like for/sum for special annotation. Also allowed no annotation to be consistent with the docs.
Properly unquote in error message.

Fixes PR 13505.
Increased timeout for matrix tests
Correct the contract in Example 3 to use and/c.

Closes PR 13486.
test case for `for' repair

Provided by Ryan to go with a85a71984d.
configure: adjust mmap()/mprotect() test

Avoid aggravating SELinux.
catch module-not-available mimatches earlier
add a test case

related to PR 13505
try to make the bug report form more robust when the
attempt to get the (nonexistent) captcha fails
Adjust keybinding code to fall back from
get-active-canvas to get-canvas

Unclear if this is a bug in get-active-canvas or not

closes PR 13507
Use up-to-date struct syntax in example