Refactor prng* from cpp macros into inline functions.

Remove 32-bit variant, convert prng64() to prng_lg_range(), and add
prng_range().

test/unit/prng.c

@@ -0,0 +1,68 @@
+#include "test/jemalloc_test.h"
+
+TEST_BEGIN(test_prng_lg_range)
+{
+	uint64_t sa, sb, ra, rb;
+	unsigned lg_range;
+
+	sa = 42;
+	ra = prng_lg_range(&sa, 64);
+	sa = 42;
+	rb = prng_lg_range(&sa, 64);
+	assert_u64_eq(ra, rb,
+	    "Repeated generation should produce repeated results");
+
+	sb = 42;
+	rb = prng_lg_range(&sb, 64);
+	assert_u64_eq(ra, rb,
+	    "Equivalent generation should produce equivalent results");
+
+	sa = 42;
+	ra = prng_lg_range(&sa, 64);
+	rb = prng_lg_range(&sa, 64);
+	assert_u64_ne(ra, rb,
+	    "Full-width results must not immediately repeat");
+
+	sa = 42;
+	ra = prng_lg_range(&sa, 64);
+	for (lg_range = 63; lg_range > 0; lg_range--) {
+		sb = 42;
+		rb = prng_lg_range(&sb, lg_range);
+		assert_u64_eq((rb & (UINT64_C(0xffffffffffffffff) << lg_range)),
+		    0, "High order bits should be 0, lg_range=%u", lg_range);
+		assert_u64_eq(rb, (ra >> (64 - lg_range)),
+		    "Expected high order bits of full-width result, "
+		    "lg_range=%u", lg_range);
+	}
+}
+TEST_END
+
+TEST_BEGIN(test_prng_range)
+{
+	uint64_t range;
+#define	MAX_RANGE	10000000
+#define	RANGE_STEP	97
+#define	NREPS		10
+
+	for (range = 2; range < MAX_RANGE; range += RANGE_STEP) {
+		uint64_t s;
+		unsigned rep;
+
+		s = range;
+		for (rep = 0; rep < NREPS; rep++) {
+			uint64_t r = prng_range(&s, range);
+
+			assert_u64_lt(r, range, "Out of range");
+		}
+	}
+}
+TEST_END
+
+int
+main(void)
+{
+
+	return (test(
+	    test_prng_lg_range,
+	    test_prng_range));
+}