Extend test to make sure IntlCalendar::clear() resets month to 0

[andypost]

Related to #11128

This test with ICU 73.1 fails with but pass earlier versions showing that clear() does not reset to 0

TEST 1/1 [ext/intl/tests/calendar_clear_variation1.phpt]
========DIFF========
--
     bool(true)
     bool(false)
     int(1)
005- float(1327813567000)
005+ float(1330491967000)
     bool(true)
     float(1327813567000)
     float(1327813567000)
--
========DONE========
FAIL IntlCalendar::clear() 1 arg variation [ext/intl/tests/calendar_clear_variation1.phpt] 

[andypost]

New change demonstrating that clear in 73.1 resets to 1 but was 0 in earlier versions - pipeline job

========DIFF========
     bool(true)
     bool(true)
     bool(false)
004- int(1)
004+ int(0)
     float(1327813567000)
     bool(true)
     float(1327813567000)
--
========DONE========

[andypost]

this should be 0 but 1 with new ICU