[lldb] add RISCV target specific info in API tests

Add information about RISCV first register in python API testsuite, that
is used to check register readability in tests.

Fixed tests on RISCV target:

TestBreakpointByFileColonLine.BreakpointByLineAndColumnTestCase
TestAddressBreakpoints.AddressBreakpointTestCase
TestBreakpointAutoContinue.BreakpointAutoContinue
TestInterruptBacktrace.TestInterruptingBacktrace
TestBadAddressBreakpoints.BadAddressBreakpointTestCase
TestScriptedResolver.TestScriptedResolver
TestStopHookScripted.TestStopHooks
TestBreakpointConditions.BreakpointConditionsTestCase
TestLocalVariables.LocalVariablesTestCase
TestFindLineEntry.FindLineEntry
TestScriptedResolver.TestScriptedResolver
TestInlineSourceFiles.InlineSourceFilesTestCase
TestModuleAndSection.ModuleAndSectionAPIsTestCase
TestFrameVar.TestFrameVar
TestInferiorAssert.AssertingInferiorTestCase
TestInferiorCrashing.CrashingInferiorTestCase
TestInferiorCrashingStep.CrashingInferiorStepTestCase
TestRegistersIterator.RegistersIteratorTestCase
TestCoroutineHandle.TestCoroutineHandle
TestWithLimitDebugInfo.TestWithLimitDebugInfo
TestLLDBIterator.LLDBIteratorTestCase
TestMemoryWrite.MemoryWriteTestCase
TestNestedTemplate.NestedTemplateTestCase
TestParrayVrsCharArrayChild.TestParrayVrsCharArrayChild
TestRecursiveInferior.CrashingRecursiveInferiorTestCase
TestRecursiveInferiorStep.CrashingRecursiveInferiorStepTestCase
TestRunLocker.TestRunLocker
TestSampleTest.RenameThisSampleTestTestCase
TestUniqueTypes3.UniqueTypesTestCase3
TestPrintStackTraces.ThreadsStackTracesTestCase
TestUnicodeSymbols.TestUnicodeSymbols
TestUnusedInlinedParameters.TestUnusedInlinedParameters
TestValueVarUpdate.ValueVarUpdateTestCase
TestPtrRef2Typedef.PtrRef2TypedefTestCase
TestDataFormatterStdIterator.StdIteratorDataFormatterTestCase
TestDataFormatterStdString.StdStringDataFormatterTestCase
TestDataFormatterStdVBool.StdVBoolDataFormatterTestCase

Author: dlav-sc

lldb/packages/Python/lldbsuite/test/lldbplatformutil.py

@@ -34,6 +34,8 @@ def check_first_register_readable(test_case):
         test_case.expect("register read r0", substrs=["r0 = 0x"])
     elif arch in ["powerpc64le"]:
         test_case.expect("register read r0", substrs=["r0 = 0x"])
+    elif re.match("^rv(32|64)", arch):
+        test_case.expect("register read zero", substrs=["zero = 0x"])
     else:
         # TODO: Add check for other architectures
         test_case.fail(