Fix bug in PATH cleaning, more robust installation detection

The previous implementation gobbled up the first entry of the PATH by interpreting the second argument as pattern.
New implementation avoids this and is more robust in detecting existing KLEE installations.

scripts/build/run-tests.sh

@@ -37,10 +37,14 @@ run_tests() {
   # TODO change to pinpoint specific directory
   cd "${build_dir}"
 
-  # Remove klee from PATH
-  export PATH=${PATH/":/home/klee/klee_build/bin"/}
+  # Remove klee from PATH. The goal is that for test cases klee is referenced via `%klee` not accidently being picked up via PATH
   if which klee; then
-    return 1 # should not happen
+    full_path_to_klee="$(which klee)"
+    target_directory="$(dirname "${full_path_to_klee}")"
+    PATH=${PATH/$target_directory/}
+    if which klee; then
+      return 1 # should not happen
+    fi
   fi
 
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