[FunC] Enrich testing framework, add fif output patterns

* @fif_codegen to match compiled.fif against an expected pattern
* @fif_codegen_avoid to ensure compiled.fif doesn't contain a substring
* both in Python and JS run_tests
* consider tests/codegen_check_demo.fc for examples

crypto/func/auto-tests/tests/codegen_check_demo.fc

@@ -0,0 +1,95 @@
+int test1() method_id(101) {
+    var x = false;
+    if (x == true) {
+        x = 100500;
+    }
+    return x;
+}
+
+_ main(s) {
+    var (z, t) = (17, s);
+    while (z > 0) {
+        t = s;
+        z -= 1;
+    }
+    return ~ t;
+}
+
+{-
+    method_id | in | out
+TESTCASE | 0   | 1  | -2
+TESTCASE | 0   | 5  | -6
+TESTCASE | 101 |    | 0
+
+Below, I just give examples of @fif_codegen tag:
+* a pattern can be single-line (after the tag), or multi-line, surrounded with """
+* there may be multiple @fif_codegen, they all will be checked
+* identation (spaces) is not checked intentionally
+* "..." means any number of any lines
+* lines not divided with "..." are expected to be consecutive in fif output
+* //comments can be omitted, but if present, they are also expected to be equal
+* there is also a tag @fif_codegen_avoid to check a pattern does not occur
+
+@fif_codegen
+"""
+main PROC:<{
+  // s
+  17 PUSHINT     //  s _3=17
+  OVER           //  s z=17 t
+  WHILE:<{
+    ...
+  }>DO<{ //  s z t
+    ...
+    s1 s(-1) PUXC //  s t z
+    ...
+  2 1 BLKDROP2
+  ...
+}>
+"""
+
+@fif_codegen
+"""
+main PROC:<{
+  ...
+  WHILE:<{
+    ...
+           }>DO<{
+  ...
+    }>
+        }END>c
+"""
+
+@fif_codegen
+"""
+    OVER
+    0 GTINT   //  s z t _5
+"""
+
+@fif_codegen
+"""
+  "Asm.fif" include
+  ...
+  PROGRAM{
+  ...
+  }END>c
+"""
+
+@fif_codegen
+"""
+test1 PROC:<{
+//
+FALSE
+}>
+"""
+
+@fif_codegen NOT //  _8
+@fif_codegen main PROC:<{
+
+@fif_codegen_avoid PROCINLINE
+@fif_codegen_avoid END c
+@fif_codegen_avoid
+"""
+multiline
+can also be
+"""
+-}