[BUG] stringfunction substring may cause heap-buffer-overflow

[stdpain]

Describe the bug

==3930==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x60c000000878 at pc 0x000000ae00ce bp 0x7ffeb16aa660 sp 0x7ffeb16aa658
READ of size 8 at 0x60c000000878 thread T0
    #0 0xae00cd in doris::StringFunctions::substring(doris_udf::FunctionContext*, doris_udf::StringVal const&, doris_udf::IntVal const&, doris_udf::IntVal const&) ../src/exprs/string_functions.cpp:98
    #1 0xa3f24e in doris::StringFunctionsTest_substring_Test::TestBody() ../test/exprs/string_functions_test.cpp:295
    #2 0x15d9d2d in void testing::internal::HandleSehExceptionsInMethodIfSupported<testing::Test, void>(testing::Test*, void (testing::Test::*)(), char const*) (/opt/stdpain/doris/baidu/bdg/doris/core/be/ut_build_ASAN/test/exprs/string_functions_test+0x15d9d2d)
    #3 0x15d4bef in void testing::internal::HandleExceptionsInMethodIfSupported<testing::Test, void>(testing::Test*, void (testing::Test::*)(), char const*) (/opt/stdpain/doris/baidu/bdg/doris/core/be/ut_build_ASAN/test/exprs/string_functions_test+0x15d4bef)
    #4 0x15bb21b in testing::Test::Run() (/opt/stdpain/doris/baidu/bdg/doris/core/be/ut_build_ASAN/test/exprs/string_functions_test+0x15bb21b)
    #5 0x15bba45 in testing::TestInfo::Run() (/opt/stdpain/doris/baidu/bdg/doris/core/be/ut_build_ASAN/test/exprs/string_functions_test+0x15bba45)
    #6 0x15bc092 in testing::TestCase::Run() (/opt/stdpain/doris/baidu/bdg/doris/core/be/ut_build_ASAN/test/exprs/string_functions_test+0x15bc092)
    #7 0x15c28fd in testing::internal::UnitTestImpl::RunAllTests() (/opt/stdpain/doris/baidu/bdg/doris/core/be/ut_build_ASAN/test/exprs/string_functions_test+0x15c28fd)
    #8 0x15dad0a in bool testing::internal::HandleSehExceptionsInMethodIfSupported<testing::internal::UnitTestImpl, bool>(testing::internal::UnitTestImpl*, bool (testing::internal::UnitTestImpl::*)(), char const*) (/opt/stdpain/doris/baidu/bdg/doris/core/be/ut_build_ASAN/test/exprs/string_functions_test+0x15dad0a)
    #9 0x15d58c1 in bool testing::internal::HandleExceptionsInMethodIfSupported<testing::internal::UnitTestImpl, bool>(testing::internal::UnitTestImpl*, bool (testing::internal::UnitTestImpl::*)(), char const*) (/opt/stdpain/doris/baidu/bdg/doris/core/be/ut_build_ASAN/test/exprs/string_functions_test+0x15d58c1)
    #10 0x15c1643 in testing::UnitTest::Run() (/opt/stdpain/doris/baidu/bdg/doris/core/be/ut_build_ASAN/test/exprs/string_functions_test+0x15c1643)
    #11 0xa7f918 in RUN_ALL_TESTS() (/opt/stdpain/doris/baidu/bdg/doris/core/be/ut_build_ASAN/test/exprs/string_functions_test+0xa7f918)
    #12 0xa74d55 in main ../test/exprs/string_functions_test.cpp:642
    #13 0x7f7afa4d3b8a in __libc_start_main ../csu/libc-start.c:308
    #14 0x9609b9 in _start (/opt/stdpain/doris/baidu/bdg/doris/core/be/ut_build_ASAN/test/exprs/string_functions_test+0x9609b9)

To Reproduce

select substring('abc', 0, 2);