tree-wide: drop de-constifying casts for strv iteration

When the the iterator variable is declared automatically, it "inherits" the
const/non-const status from the argument. We don't need to cast a const
table to non-const. If we had a programming error and tried to modify the
string, the compiler could now catch this.

src/test/test-fs-util.c

@@ -712,7 +712,7 @@ TEST(rename_noreplace) {
         j = strjoina(z, table[4]);
         (void) symlink("foobar", j);
 
-        STRV_FOREACH(a, (char**) table) {
+        STRV_FOREACH(a, table) {
                 _cleanup_free_ char *x = NULL, *y = NULL;
 
                 x = strjoin(z, *a);
@@ -723,7 +723,7 @@ TEST(rename_noreplace) {
                         continue;
                 }
 
-                STRV_FOREACH(b, (char**) table) {
+                STRV_FOREACH(b, table) {
                         _cleanup_free_ char *w = NULL;
 
                         w = strjoin(z, *b);

src/test/test-sysctl-util.c

@@ -27,7 +27,7 @@ static const char* const cases[] = {
 };
 
 TEST(sysctl_normalize) {
-        STRV_FOREACH_PAIR(s, expected, (const char**) cases) {
+        STRV_FOREACH_PAIR(s, expected, cases) {
                 _cleanup_free_ char *t;
 
                 assert_se(t = strdup(*s));