[Flang] test_symbols.py module file fix

Due to how the LIT deals with module files,
this change stores and runs the scripts in
their own temporary directory to prevent
interference in-between different tests.
It also makes ``test_symbols.py`` be more
consistent with the other scripts.

Reviewed By: Meinersbur, awarzynski

Differential Revision: https://reviews.llvm.org/D107953

Author: Ivan Zhechev

flang/test/Semantics/test_symbols.py

@@ -3,10 +3,14 @@
 """Compiles a source file with "-fdebug-unparse-with-symbols' and verifies
 we get the right symbols in the output, i.e. the output should be
 the same as the input, except for the copyright comment.
-Expects a source file passed as the first argument;
-Expects the Flang frontend driver with options as second argument."""
+
+Parameters:
+    sys.argv[1]: a source file with contains the input and expected output
+    sys.argv[2]: the Flang frontend driver
+    sys.argv[3:]: Optional arguments to the Flang frontend driver"""
 
 import sys
+import tempfile
 import re
 import subprocess
 import common as cm
@@ -36,7 +40,8 @@
 
 # Compiles, inserting comments for symbols:
 cmd = [flang_fc1, *flang_fc1_args, flang_fc1_options]
-diff3 = subprocess.check_output(cmd, input=diff2, universal_newlines=True)
+with tempfile.TemporaryDirectory() as tmpdir:
+    diff3 = subprocess.check_output(cmd, input=diff2, universal_newlines=True, cwd=tmpdir)
 
 # Removes all whitespace to compare differences in files
 diff1 = diff1.replace(" ", "")