Extended printf test with new strings cases (#1951)

According to work plan from issue #1058

Corrections to general test:
-removed duplication of separate tests for each element of
`PrintfTestType` vector, instead `doTest` procedure would iterate over
vector related to specific `PrintfTestType` automaticaly
-fixed procedure to assemble kernel source so it can accept only one
parameter of the function ( eg. `printf("%%");` )
-incorporated important modifications from #1940 to avoid expected
conflicts
-warnings fixes, minor corrections, clang format

Extension for string testing:
-special symbols
-nested symbols
-all ascii characters 
-added new type of test `TYPE_FORMAT_STRING` to verify format string
only (according to request from the issue)

test_conformance/printf/test_printf.h

@@ -55,6 +55,7 @@ enum PrintfTestType
     TYPE_HEXADEC,
     TYPE_CHAR,
     TYPE_STRING,
+    TYPE_FORMAT_STRING,
     TYPE_VECTOR,
     TYPE_ADDRESS_SPACE,
     TYPE_COUNT