[lldb] Update two API tests to fix x86 Darwin failures

The Intel Darwin CI bots had their Xcode updated, which brought in
a debugserver with Brendan Shanks' change from September
7281e0c
#108663 where four general
purpose registers are sent by debugserver when in certain process
states.  But most processes (nearly all in the testsuite) do not
have these registers available, so we will get register read failures
when requesting those four.  These two tests would flag those as
errors.  There would have been an additional problem with the g/G
packet (which lldb doesn't use w/ debugserver, but the testsuite
tests) if placeholder values were not included in the full register
context bytes; I fixed that issue with the SME patch to debugserver
recently already.

Author: jasonmolenda

lldb/packages/Python/lldbsuite/test/tools/lldb-server/gdbremote_testcase.py

@@ -1410,7 +1410,17 @@ def read_register_values(self, reg_infos, endian, thread_id=None):
             p_response = context.get("p_response")
             self.assertIsNotNone(p_response)
             self.assertTrue(len(p_response) > 0)
-            self.assertFalse(p_response[0] == "E")
+
+            # on x86 Darwin, 4 GPR registers are often
+            # unavailable, this is expected and correct.
+            if (
+                self.getArchitecture() == "x86_64"
+                and self.platformIsDarwin()
+                and p_response[0] == "E"
+            ):
+                values[reg_index] = 0
+            else:
+                self.assertFalse(p_response[0] == "E")
 
             values[reg_index] = unpack_register_hex_unsigned(endian, p_response)
 

lldb/test/API/commands/register/register/register_command/TestRegisters.py

@@ -58,6 +58,13 @@ def test_register_commands(self):
             # could not be read.  This is expected.
             error_str_matched = True
 
+        if self.getArchitecture() == "x86_64" and self.platformIsDarwin():
+            # debugserver on x86 will provide ds/es/ss/gsbase when the
+            # kernel provides them, but most of the time they will be
+            # unavailable.  So "register read -a" will report that
+            # 4 registers were unavailable, it is expected.
+            error_str_matched = True
+
         self.expect(
             "register read -a",
             MISSING_EXPECTED_REGISTERS,