Augment uncaught-exception.test fuzzer test to be msvc-compatible (#125924)

Today, the `uncaught-exception.test` fuzzer test checks for the string
"libFuzzer: deadly signal" in the program output as the result of an
uncaught exception.

Although this is correct for `clang`, `msvc` reports a different error
message: "libFuzzer: uncaught C++ exception". Since `msvc` reuses the
`libFuzzer` infrastructure for ASan regression testing, it would help us
greatly if the test handled the `msvc` divergence more gracefully.

**This PR:** augments this test so check for a different string (namely
"libFuzzer: uncaught C++ exception") if the compiler target matches the
`msvc` naming scheme.

I understand if this is outside the scope of support for LLVM as well,
and I'm also open for different approaches here. Thanks!

Author: davidmrdavid

compiler-rt/test/fuzzer/uncaught-exception.test

@@ -4,7 +4,10 @@
 REQUIRES: windows
 RUN: %cpp_compiler %S/UncaughtException.cpp -o %t-UncaughtException
 
-RUN: not %run %t-UncaughtException 2>&1 | FileCheck %s
+# Clang will fail the test with 'deadly signal', but other compilers may fail with different error messages.
+# For example, msvc fails with 'uncaught C++ exception'. So the error we check depends on the compiler target.
+RUN: not %run %t-UncaughtException 2>&1 | FileCheck %s --check-prefixes=CHECK-CRASH,%if target={{.*-windows-msvc.*}} %{CHECK-MSVC%} %else %{CHECK-ERROR%}
 
-CHECK: ERROR: libFuzzer: deadly signal
-CHECK: Test unit written to ./crash
+CHECK-ERROR: ERROR: libFuzzer: deadly signal
+CHECK-MSVC: ERROR: libFuzzer: uncaught C++ exception
+CHECK-CRASH: Test unit written to ./crash