[libc] Fix GPU test build error

This fixes a build error on the AMDGPU buildbot introduced in PR
#92172

Author: jplehr

libc/src/__support/StringUtil/tables/stdc_errors.h

@@ -15,11 +15,10 @@
 
 namespace LIBC_NAMESPACE {
 
-LIBC_INLINE_VAR constexpr const MsgTable<4> STDC_ERRORS = {
+LIBC_INLINE_VAR constexpr const MsgTable<3> STDC_ERRORS = {
     MsgMapping(0, "Success"),
     MsgMapping(EDOM, "Numerical argument out of domain"),
     MsgMapping(ERANGE, "Numerical result out of range"),
-    MsgMapping(EILSEQ, "Invalid or incomplete multibyte or wide character"),
 };
 
 } // namespace LIBC_NAMESPACE

libc/test/src/string/strerror_test.cpp

@@ -97,7 +97,7 @@ TEST(LlvmLibcStrErrorTest, KnownErrors) {
       ".lib section in a.out corrupted",
       "Attempting to link in too many shared libraries",
       "Cannot exec a shared library directly",
-      "Invalid or incomplete multibyte or wide character",
+      "Unknown Error 84", // Unknown
       "Interrupted system call should be restarted",
       "Streams pipe error",
       "Too many users",