target/ppc: Moved XSTSTDC[QDS]P to decodetree

target/ppc: Moved XSTSTDC[QDS]P to decodetree

Moved XSTSTDCSP, XSTSTDCDP and XSTSTDCQP to decodetree and moved some of
its decoding away from the helper as previously the DCMX, XB and BF were
calculated in the helper with the help of cpu_env, now that part was
moved to the decodetree with the rest.

xvtstdcsp:
rept    loop    master             patch
8       12500   1,85393600         1,94683600 (+5.0%)
25      4000    1,78779800         1,92479000 (+7.7%)
100     1000    2,12775000         2,28895500 (+7.6%)
500     200     2,99655300         3,23102900 (+7.8%)
2500    40      6,89082200         7,44827500 (+8.1%)
8000    12     17,50585500        18,95152100 (+8.3%)

xvtstdcdp:
rept    loop    master             patch
8       12500   1,39043100         1,33539800 (-4.0%)
25      4000    1,35731800         1,37347800 (+1.2%)
100     1000    1,51514800         1,56053000 (+3.0%)
500     200     2,21014400         2,47906000 (+12.2%)
2500    40      5,39488200         6,68766700 (+24.0%)
8000    12     13,98623900        18,17661900 (+30.0%)

xvtstdcdp:
rept    loop    master             patch
8       12500   1,35123800         1,34455800 (-0.5%)
25      4000    1,36441200         1,36759600 (+0.2%)
100     1000    1,49763500         1,54138400 (+2.9%)
500     200     2,19020200         2,46196400 (+12.4%)
2500    40      5,39265700         6,68147900 (+23.9%)
8000    12     14,04163600        18,19669600 (+29.6%)

As some values are now decoded outside the helper and passed to it as an
argument the number of arguments of the helper increased, the number
of TCGop needed to load the arguments increased. I suspect that's why
the slow-down in the tests with a high REPT but low LOOP.

Signed-off-by: Lucas Mateus Castro (alqotel) <lucas.araujo@eldorado.org.br>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20221019125040.48028-12-lucas.araujo@eldorado.org.br>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>