generate_psa_tests.py does not work on non-English versions of Visual Studio
Reported in https://github.com/ARMmbed/mbedtls/issues/2188#issuecomment-865502961:

> `scripts\\make_generated_files.bat` doesn't work out of the box because I'm using visual studio with Chinese language. The cl.exe output is not match `Microsoft (R) C/C++ Optimizing Compiler` but `Microsoft (R) C/C++ 优化编译器`

Since we don't ship the generated files on the development branch, `generate_psa_tests.py` is somewhat user-facing (only for users who use the development version, not for users of released versions where the files are pre-generated). It's invoked by `scripts\\make_generated_files.bat` which is mentioned in `README.md`.

diff --git a/scripts/mbedtls_dev/c_build_helper.py b/scripts/mbedtls_dev/c_build_helper.py
index 18c1e7606..459afba42 100644
--- a/scripts/mbedtls_dev/c_build_helper.py
+++ b/scripts/mbedtls_dev/c_build_helper.py
@@ -135,8 +135,7 @@ def get_c_expression_values(
                                 stdout=subprocess.DEVNULL,
                                 stderr=subprocess.PIPE,
                                 universal_newlines=True)
-        cc_is_msvc = 'Microsoft (R) C/C++ Optimizing Compiler' in \\
-                      proc.communicate()[1]
+        cc_is_msvc = 'Microsoft (R) C/C++' in proc.communicate()[1]
 
         cmd += ['-I' + dir for dir in include_path]
         if cc_is_msvc:
['scripts/mbedtls_dev/c_build_helper.py']