fix: Ensure local simplecpp executable is used in tests

This change ensures that the local simplecpp executable is used instead of any
random executable found in the PATH.

Suggested-by: firewave <firewave@users.noreply.github.com>

Author: jcfr

run-tests.py

@@ -26,13 +26,11 @@ def cleanup(out: str) -> str:
 if not GCC_EXE:
     sys.exit('Failed to run tests: gcc compiler not found')
 
-# Check if simplecpp is in the PATH
-SIMPLECPP_EXE = shutil.which('simplecpp')
-# If not found in PATH, try current directory
-if not SIMPLECPP_EXE:
-    candidate = os.path.join(os.getcwd(), "simplecpp")
-    if os.path.isfile(candidate) and os.access(candidate, os.X_OK):
-        SIMPLECPP_EXE = candidate
+# Ensure the local simplecpp executable is used
+SIMPLECPP_EXE = None
+candidate = os.path.join(os.getcwd(), 'simplecpp')
+if os.path.isfile(candidate) and os.access(candidate, os.X_OK):
+    SIMPLECPP_EXE = candidate
 if not SIMPLECPP_EXE:
     sys.exit('Failed to run tests: simplecpp compiler not found')