github: Run the libcxx tests with "-v --time-tests"

This allows seeing the names of tests as they are executed, making
the intermediate log output on github actions more useful. It
also makes it easier to correlate test issues between tests as
they are executed (e.g. if one test causes another one to run out
of memory).

Also run with --time-tests, allowing identifying slow tests.

This was already applied in the separate libcxx test job added in
7483eae; this backports the change
into the test job in the main build file.

Author: mstorsjo

.github/workflows/build.yml

@@ -382,7 +382,8 @@ jobs:
             -DLIBCXXABI_USE_COMPILER_RT=YES `
             -DLIBUNWIND_USE_COMPILER_RT=YES `
             -DLIBCXXABI_USE_LLVM_UNWINDER=YES `
-            -DLIBCXX_EXTRA_SITE_DEFINES="__USE_MINGW_ANSI_STDIO=1;TEST_IS_EXECUTED_IN_A_SLOW_ENVIRONMENT"
+            -DLIBCXX_EXTRA_SITE_DEFINES="__USE_MINGW_ANSI_STDIO=1;TEST_IS_EXECUTED_IN_A_SLOW_ENVIRONMENT" `
+            -DLLVM_LIT_ARGS="-v --time-tests"
           ninja
           ninja check-cxx check-cxxabi check-unwind