trv: Moved fixgrm into lfs3_mtree_gc

Whoops, we still need the low-level grm check in lfs3_mtree_gc.

This is not an optimization, we simply don't support deleting
files/orphans with pending grms as those grms will likely fall
out-of-date. So we need to flush the grm queue before any fixorphan
work.

And the check in lfs3_trv_read does not handle the other gc APIs.

This correctly fails tests when ran with LFS3_GC=1.

---

Code changes minimal:

           code          stack          ctx
  before: 35292           2136          660
  after:  35296 (+0.0%)   2136 (+0.0%)  660 (+0.0%)

lfs3.c

@@ -10179,6 +10179,7 @@ eot:;
 }
 
 // needed in lfs3_mtree_gc
+static int lfs3_fs_fixgrm(lfs3_t *lfs3);
 static int lfs3_mdir_mkconsistent(lfs3_t *lfs3, lfs3_mdir_t *mdir);
 static inline void lfs3_alloc_ckpoint_(lfs3_t *lfs3);
 static inline bool lfs3_alloc_canlookahead(const lfs3_t *lfs3);
@@ -10196,6 +10197,22 @@ static int lfs3_alloc_adoptgbmap(lfs3_t *lfs3,
 // mutation here
 static lfs3_stag_t lfs3_mtree_gc(lfs3_t *lfs3, lfs3_mgc_t *mgc,
         lfs3_bptr_t *bptr_) {
+    // check for pending grms every step, just in case some other
+    // operation introduced new grms
+    #ifndef LFS3_RDONLY
+    if (lfs3_t_ismkconsistent(mgc->t.h.flags)
+            && lfs3_grm_count(lfs3) > 0) {
+        // fix pending grms
+        uint32_t dirty = mgc->t.h.flags;
+        int err = lfs3_fs_fixgrm(lfs3);
+        if (err) {
+            return err;
+        }
+        // reset dirty flag
+        mgc->t.h.flags &= ~LFS3_t_DIRTY | dirty;
+    }
+    #endif
+
     // start of traversal?
     if (mgc->t.h.mdir.mid == LFS3_MID_MROOTANCHOR) {
         #ifndef LFS3_RDONLY
@@ -11692,9 +11709,6 @@ empty:;
 }
 #endif
 
-// needed in lfs3_remove
-static int lfs3_fs_fixgrm(lfs3_t *lfs3);
-
 #ifndef LFS3_RDONLY
 int lfs3_remove(lfs3_t *lfs3, const char *path) {
     // prepare our filesystem for writing
@@ -17159,22 +17173,6 @@ int lfs3_trv_read(lfs3_t *lfs3, lfs3_trv_t *trv,
         return LFS3_ERR_BUSY;
     }
 
-    // check for pending grms every step, just in case some other
-    // operation introduced new grms
-    #ifndef LFS3_RDONLY
-    if (lfs3_t_ismkconsistent(trv->gc.t.h.flags)
-            && lfs3_grm_count(lfs3) > 0) {
-        // fix pending grms
-        uint32_t dirty = trv->gc.t.h.flags;
-        int err = lfs3_fs_fixgrm(lfs3);
-        if (err) {
-            return err;
-        }
-        // reset dirty flag
-        trv->gc.t.h.flags &= ~LFS3_t_DIRTY | dirty;
-    }
-    #endif
-
     // discard current block queue?
     if (lfs3_t_isstale(trv->gc.t.h.flags)) {
         trv->blocks[0] = -1;