gh-130317: Fix SNaN broken tests on HP PA RISC (#140452)

While looking at #140028, I found some unrelated test regressions in the
3.14 cycle. These seem to all come from #130317. From what I can tell,
that made Python more correct than it was before. According to [0], HP PA
RISC uses 1 for SNaN and thus a 0 for QNaN.

[0]: https://grouper.ieee.org/groups/1788/email/msg03272.html

Lib/test/test_capi/test_float.py

@@ -1,5 +1,6 @@
 import math
 import random
+import platform
 import sys
 import unittest
 import warnings
@@ -197,6 +198,10 @@ def test_pack_unpack_roundtrip_for_nans(self):
                     # PyFloat_Pack/Unpack*() API.  See also gh-130317 and
                     # e.g. https://developercommunity.visualstudio.com/t/155064
                     signaling = 0
+                    if platform.machine().startswith('parisc'):
+                        # HP PA RISC uses 0 for quiet, see:
+                        # https://en.wikipedia.org/wiki/NaN#Encoding
+                        signaling = 1
                 quiet = int(not signaling)
                 if size == 8:
                     payload = random.randint(signaling, 0x7ffffffffffff)