Create pending edge from continue when loop has at least one iteration (PY-29767)

There is no edge between loop statement and next after loop instruction
when loop has at least one iteration
so `continue` is marked as one more last instruction in the loop

python/testData/codeInsight/controlflow/continueinpositiveiteration.py

@@ -0,0 +1,7 @@
+import sys
+
+for s in "abc":
+    if len(s) == 1:
+        continue
+    sys.exit(0)
+raise Exception("the end")

python/testData/codeInsight/controlflow/continueinpositiveiteration.txt

@@ -0,0 +1,16 @@
+0(1) element: null
+1(2) element: PyImportStatement
+2(3) WRITE ACCESS: sys
+3(4) element: PyForStatement
+4(5) element: PyTargetExpression: s
+5(6) WRITE ACCESS: s
+6(7) element: PyIfStatement
+7(8) READ ACCESS: len
+8(9,11) READ ACCESS: s
+9(10) element: PyStatementList. Condition: len(s) == 1:true
+10(3,13) element: PyContinueStatement
+11(12) element: PyExpressionStatement
+12(15) READ ACCESS: sys
+13(14) element: PyRaiseStatement
+14(15) READ ACCESS: Exception
+15() element: null

python/testData/codeInsight/controlflow/trytry.txt

@@ -23,7 +23,7 @@
 22(23,37) element: PyIfPartElif. Condition: x == 0:false
 23(24,26,37) READ ACCESS: x
 24(25) element: PyStatementList. Condition: x == 1:true
-25(7,37) element: PyContinueStatement
+25(7,37,40) element: PyContinueStatement
 26(27,37) element: PyIfPartElif. Condition: x == 1:false
 27(28,31,37) READ ACCESS: x
 28(29) element: PyStatementList. Condition: x == 2:true