[clang] [analyzer][Z3] Restore the original timeout of 15s (PR #118291)

[Balazs Benics via cfe-commits]

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@@ -74,13 +74,13 @@ TEST_F(Z3CrosscheckOracleTest, SATWhenItGoesOverTime) {
 }
 
 TEST_F(Z3CrosscheckOracleTest, UNSATWhenItGoesOverTime) {
-  ASSERT_EQ(RejectEQClass, interpretQueryResult({UNSAT, 310_ms, 1000_step}));
+  ASSERT_EQ(RejectReport, interpretQueryResult({UNSAT, 310_ms, 1000_step}));
 }
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steakhal wrote:

I don't think these test reflect what they were testing anymore. Similar argument goes for the rest of the test cases.
The test name suggests `UNSATWhenItGoesOverTime`, so we should pass a time that meets this scenario with the new timeout of 15 seconds. I suppose `15'010_ms` should suffice.

It would be also nice if we could showcase the difference of the non-default (previous) config with using 400k rlimit and 300ms timeout to see if the behavior still meets the expected behavior of we had.
It shouldn't be much of a burden to create that config - similar how the `DefaultOpts` is made, and basically copy-paste the original tests. We could have a separate fixture for it, called `Z3CrosscheckDefaultOracleTest` and a `Z3CrosscheckCustomOracleTest` where the defaults are overridden. This way even the PR diff would look nice.

https://github.com/llvm/llvm-project/pull/118291