Remove memory leaks in isolationtester.

specscanner.l leaked a kilobyte of memory per token of the spec file.
Apparently somebody thought that the introductory code block would be
executed once; but it's once per yylex() call.

A couple of functions in isolationtester.c leaked small amounts of
memory due to not bothering to free one-time allocations.  Might
as well improve these so that valgrind gives this program a clean
bill of health.  Also get rid of an ugly static variable.

Coverity complained about one of the one-time leaks, which led me
to try valgrind'ing isolationtester, which led to discovery of the
larger leak.

src/test/isolation/isolationtester.c

@@ -52,8 +52,8 @@ static int64 max_step_wait = 300 * USECS_PER_SEC;
 static void check_testspec(TestSpec *testspec);
 static void run_testspec(TestSpec *testspec);
 static void run_all_permutations(TestSpec *testspec);
-static void run_all_permutations_recurse(TestSpec *testspec, int nsteps,
-										 PermutationStep **steps);
+static void run_all_permutations_recurse(TestSpec *testspec, int *piles,
+										 int nsteps, PermutationStep **steps);
 static void run_named_permutations(TestSpec *testspec);
 static void run_permutation(TestSpec *testspec, int nsteps,
 							PermutationStep **steps);
@@ -360,9 +360,9 @@ check_testspec(TestSpec *testspec)
 				fprintf(stderr, "unused step name: %s\n", allsteps[i]->name);
 		}
 	}
-}
 
-static int *piles;
+	free(allsteps);
+}
 
 /*
  * Run the permutations specified in the spec, or all if none were
@@ -387,6 +387,7 @@ run_all_permutations(TestSpec *testspec)
 	int			i;
 	PermutationStep *steps;
 	PermutationStep **stepptrs;
+	int		   *piles;
 
 	/* Count the total number of steps in all sessions */
 	nsteps = 0;
@@ -412,11 +413,16 @@ run_all_permutations(TestSpec *testspec)
 	for (i = 0; i < testspec->nsessions; i++)
 		piles[i] = 0;
 
-	run_all_permutations_recurse(testspec, 0, stepptrs);
+	run_all_permutations_recurse(testspec, piles, 0, stepptrs);
+
+	free(steps);
+	free(stepptrs);
+	free(piles);
 }
 
 static void
-run_all_permutations_recurse(TestSpec *testspec, int nsteps, PermutationStep **steps)
+run_all_permutations_recurse(TestSpec *testspec, int *piles,
+							 int nsteps, PermutationStep **steps)
 {
 	int			i;
 	bool		found = false;
@@ -438,7 +444,7 @@ run_all_permutations_recurse(TestSpec *testspec, int nsteps, PermutationStep **s
 
 			piles[i]++;
 
-			run_all_permutations_recurse(testspec, nsteps + 1, steps);
+			run_all_permutations_recurse(testspec, piles, nsteps + 1, steps);
 
 			piles[i]--;
 

src/test/isolation/specscanner.l

@@ -52,8 +52,12 @@ self			[,()*]
 %%
 
 %{
-	litbuf = pg_malloc(LITBUF_INIT);
-	litbufsize = LITBUF_INIT;
+	/* Allocate litbuf in first call of yylex() */
+	if (litbuf == NULL)
+	{
+		litbuf = pg_malloc(LITBUF_INIT);
+		litbufsize = LITBUF_INIT;
+	}
 %}
 
  /* Keywords (must appear before the {identifier} rule!) */