tests: do not use ninja-build for integration testsuite

ninja-build is distributed from extra repos such as epel.
Unfortunately this is not available in all supported archs
which makes it impossible to test with ninja-build.

tests/build-gating.fmf

@@ -37,7 +37,7 @@ adjust:
     when: >-
       distro == centos
 
-  # Unfortunatelly, TMT does not support more declarative approach, we need to run commands on our own.
+  # Unfortunately, TMT does not support more declarative approach, we need to run commands on our own.
   - because: "On RHEL, CRB must be enabled to provide rarer packages"
     prepare+:
       - name: Enable CRB
@@ -47,16 +47,6 @@ adjust:
       distro == rhel-9
       or distro == rhel-8
 
-  # Unfortunatelly, TMT does not support more declarative approach, we need to run commands on our own.
-  - because: "On RHEL-7, EPEL must be enabled to provided rarer packages"
-    prepare+:
-      - name: Enable EPEL
-        how: shell
-        script: |
-          rpm -q epel-release || yum install -y https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
-          yum-config-manager --enable epel
-    when: distro == rhel-7
-
 discover:
     how: fmf
 execute:

tests/integration-test-suite/main.fmf

@@ -6,7 +6,6 @@ require:
   - git
   - make
   # These require special repositories to be enabled on RHEL
-  - ninja-build
   - libstdc++-static
 adjust:
   # Common requirements when LLVM is not SCL-ized

tests/integration-test-suite/test.sh

@@ -33,5 +33,7 @@ cd $(mktemp -d -p /var/tmp)
 git clone $repo_url
 cd llvm-toolchain-integration-test-suite
 mkdir _build && cd _build
-cmake .. -GNinja ${CMAKE_CXXLIB:-}
-cmake --build . $thread_args --target check
+cmake .. ${CMAKE_CXXLIB:-}
+# Do not run with make as it will return 2 in case of failures, which will be
+# reported by tmt as error instead failure. Run with lit so it returns 1.
+lit --show-unsupported --show-xfail -v tests