Preserve the capitalization in test data files of PyControlFlowBuilderTest

Previously, it used an odd convention with lowercased names of test data
files (with nothing separating individual words), which made adding new tests
quite tedious.

Also, I removed the test data "exit.py" as it wasn't used by any test.

GitOrigin-RevId: 92b1963c67ed01977f5b7ad020984056c9fe045d

python/testData/codeInsight/controlflow/TryTry.py

@@ -0,0 +1,27 @@
+a = 1
+try:
+    b = 2
+    for x in [1, 2, 3]: # loop:8
+        try:
+            c = 3
+            try:
+                d = 4
+                if x == 0:
+                    break
+                elif x == 1:
+                    continue
+                elif x == 2:
+                    raise Exception()
+                elif x == 3:
+                    return 42
+                e = 5
+            finally: # f:37,s:40
+                f = 6
+            g = 7
+        finally: # f:45,s:48
+            h = 8
+        i = 9
+    j = 10
+finally: # f:55,s:58
+    k = 11
+l = 12