Timeout tests : unstable result

[jeromecoutant]

Description

lp_timeout test is not 100% OK for all iterations.

RTX waits, such as sem.wait(N+1), delays for between N and N+1 cycles.

As lp_ticker is not so accurate as us_ticker, delay can be also variable around N depending on used clock.

So sometimes, in lp_timeout test, semaphore wait is expiring just before the lp_timeout, and test becomes fail.
Proposition is then to use sem.wait(N+2).
Test result becomes now 100% OK.

Thx

Pull request type

[x] Fix
[ ] Refactor
[ ] Target update
[ ] Feature
[ ] Breaking change

[0xc0170]

cc @mprse @maciejbocianski @fkjagodzinski @jamesbeyond

[fkjagodzinski]

@jeromecoutant, thanks for the fix!

[0xc0170]

/morph build

[mbed-ci]

Build : SUCCESS

Build number : 2774
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/7738/

Triggering tests

/morph test
/morph uvisor-test
/morph export-build
/morph mbed2-build

[mbed-ci]

Exporter Build : SUCCESS

Build number : 2405
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/exporter/7738/

[mbed-ci]

Test : FAILURE

Build number : 2508
Test logs :http://mbed-os-logs.s3-website-us-west-1.amazonaws.com/?prefix=logs/7738/2508

[cmonr]

/morph test

[mbed-ci]

Test : SUCCESS

Build number : 2513
Test logs :http://mbed-os-logs.s3-website-us-west-1.amazonaws.com/?prefix=logs/7738/2513