icu: Add ptest support

icu: Add ptest support

Add following patches.
  - 0001-test-Add-support-ptest.patch
    - Some default paths in test code are invalid at runtime and cause
    - test failures. So add a patch to adjust path to test data for ptest
    - environment.
  - 0001-ICU-23120-Mask-UnicodeStringTest-TestLargeMemory-on-.patch
    - Since ICU-77.1, a test case (TestLargeMemory) that fails to build
    - in a 32-bit environment. So add a patch to skip this test case.
    - This bug has been reported to upstream. See https://unicode-org.atlassian.net/browse/ICU-23120.
Install icu test-suite to run it as a ptest.
Add icu to PTESTS_FAST because it takes 27sec (less than 30sec) to complete on
qemux86-64 with kvm enabled.

root@qemux86-64:~# ptest-runner icu
START: ptest-runner
2025-07-06T00:46
BEGIN: /usr/lib/icu/ptest
___(snip)___
--------------------------------------
Elapsed Time: 00:00:23.070
PASS: ./intltest
DURATION: 27
END: /usr/lib/icu/ptest
2025-07-06T00:47
STOP: ptest-runner
TOTAL: 1 FAIL: 0

Signed-off-by: Daisuke Yamane <yamane07ynct@gmail.com>
CC: Alexander Kanavin <alex.kanavin@gmail.com>
Signed-off-by: Antonin Godard <antonin.godard@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>