[clang] [llvm] [RISCV] Remove SeenExtMap from RISCVISAInfo::parseArchString. (PR #97506)

[Pengcheng Wang via cfe-commits]

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@@ -306,7 +306,7 @@
 // RUN: not %clang --target=riscv32-unknown-elf -march=rv32ixabc_ -### %s \
 // RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32-XSEP %s
 // RV32-XSEP: error: invalid arch name 'rv32ixabc_',
-// RV32-XSEP: extension name missing after separator '_'
+// RV32-XSEP: unsupported non-standard user-level extension 'xabc'
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wangpc-pp wrote:

So there is no test coverage for `extension name missing after separator` now? Or is this error in a dead code path now?

https://github.com/llvm/llvm-project/pull/97506