This fixes the stack overflow error during the basic USB tests.
Update the ctrl_buf member of the USBTester and USBEndpointTester test
classes to be allocated on the heap. This saves 2 KB of a main stack.
Although the USB spec sets the upper limit on FS isochronous endpoint
payloads to 1023 B, this value is hard to test in practice. Moreover,
not all the targets Mbed OS supports (like NUCLEO_F207ZG) are able to
handle all the endpoints set to max.
Fix the host script issues present on Windows machines.
Add 0 B payload size to bulk endpoints test.
Update halt and abort tests according to PR comments.
Add an explicit request to start reading on OUT endpoints.