bigfile/test/test_ram: Don't forget to free allocated Page structs

test_ram is low-level test that tests RAM pages allocation/mmapping.
As allocated pages are not integrated with virtmem (not added to any
file mapping and RAM->lru_list) the Page structs have to be explicitly
freed. Fixes e.g.

	Direct leak of 80 byte(s) in 1 object(s) allocated from:
	    #0 0x7ff29af46518 in calloc (/usr/lib/x86_64-linux-gnu/libasan.so.5+0xe9518)
	    #1 0x56131dc22289 in zalloc include/wendelin/utils.h:67
	    #2 0x56131dc225d6 in ramh_alloc_page bigfile/tests/../ram.c:41
	    #3 0x56131dc2a19e in main bigfile/tests/test_ram.c:130
	    #4 0x7ff29ac9f09a in __libc_start_main ../csu/libc-start.c:308

bigfile/tests/test_ram.c

@@ -116,6 +116,10 @@ int main()
     xmunmap(p01, ps);
     xmunmap(p02, ps);
     xmunmap(p03, ps);
+    free(page0);
+    // page1: was not yet allocated
+    free(page2);
+    // page3: was not yet allocated
 
 
     /* ensure we get "no memory" when overallocating (not doing so would lead
@@ -145,6 +149,13 @@ int main()
     // TODO allocate memory amount = 2*ram_maxsize and touch it linearly
 
 
+    xmunmap(p0, ps);
+    xmunmap(p1, ps);
+    xmunmap(p2, ps);
+    free(page0);
+    free(page1);
+    free(page2);
+    ok1(!page3);
 
     ramh_close(ramh);
     ram_close(ram);