Change the use of setjmp and longjmp in signalling parameter validation failures
when using the MBEDTLS_CHECK_PARAMS config.h option. This change allows
all calls which might result in a call to the parameter validation failure
handler to always be caught, even without use of the new macros, by placing a
setjmp() in the outer function which calls the test function, which the handler
can jump to.
This has several benefits:
* it allows us to remove the clang compiler warning (-Wclobbered) caused
by local auto variables being in the same function as the call to setjmp.
* removes the need to wrap all function calls in the test functions with the
TEST_ASSERT() macro. Now all parameter validation function calls should be
caught.
Function test_snprintf() is called by run_test_snprintf() with constant test
data. It gets inlined and is subjected to snprintf format truncation checks
introduced by -Wformat-truncation in gcc-7. -Wformat-truncation is turned
On by -Wall and other similar options. It results in error with -Werror.
-Wformat-truncation makes tests performed by run_test_snprintf() redundant
on gcc. But they are still relevant for other compilers. This commit prevents
inlining of test_snprintf() to avoid gcc compile time checks.
