Fixes: NB#176803 - MLocale::formatDateTime allocates MLocale per call

RevBy: Armin Berres, John Tapsell

Details:

QString MLocale::formatDateTime(const MCalendar &mCalendar, const QString &formatString) const

did indeed allocate an extra instance of MLocale to be able to format
localized numbers according to the lc_time setting.

Instead of allocating an MLocale object for this, add another private
member to MLocale to cache another icu::NumberFormat and use this in
formatDateTime to format localized numbers.

Benchmark results using the benchmarks in the previous commit:

Old:

RESULT : Ut_MCalendar::benchmarkFormatDateTimePosixFormatString_U_QDateTime():
     0.59 msecs per iteration (total: 76, iterations: 128)
RESULT : Ut_MCalendar::benchmarkFormatDateTimePosixFormatString_U_MCalendar():
     0.57 msecs per iteration (total: 73, iterations: 128)
RESULT : Ut_MCalendar::benchmarkFormatDateTimePosixFormatString_V_MCalendar():
     0.57 msecs per iteration (total: 73, iterations: 128)
RESULT : Ut_MCalendar::benchmarkFormatDateTimePosixFormatString_r_MCalendar():
     1.3 msecs per iteration (total: 88, iterations: 64)
RESULT : Ut_MCalendar::benchmarkFormatDateTimePosixFormatString_R_MCalendar():
     1.3 msecs per iteration (total: 84, iterations: 64)
RESULT : Ut_MCalendar::benchmarkFormatDateTimePosixFormatString_t_MCalendar():
     0.53 msecs per iteration (total: 69, iterations: 128)

New:

RESULT : Ut_MCalendar::benchmarkFormatDateTimePosixFormatString_U_QDateTime():
     0.28 msecs per iteration (total: 72, iterations: 256)
RESULT : Ut_MCalendar::benchmarkFormatDateTimePosixFormatString_U_MCalendar():
     0.25 msecs per iteration (total: 66, iterations: 256)
RESULT : Ut_MCalendar::benchmarkFormatDateTimePosixFormatString_V_MCalendar():
     0.24 msecs per iteration (total: 63, iterations: 256)
RESULT : Ut_MCalendar::benchmarkFormatDateTimePosixFormatString_r_MCalendar():
     0.98 msecs per iteration (total: 63, iterations: 64)
RESULT : Ut_MCalendar::benchmarkFormatDateTimePosixFormatString_R_MCalendar():
     1.0 msecs per iteration (total: 65, iterations: 64)
RESULT : Ut_MCalendar::benchmarkFormatDateTimePosixFormatString_t_MCalendar():
     0.23 msecs per iteration (total: 60, iterations: 256)

0 files changed, 0 insertions, 0 deletions