Fix HDFFV-11101

Description
    Added initialization to local structs in the src function
    H5MF_settle_raw_data_fsm() and the test function test_bt2_hdr_fd()
    to prevent the following error in two different occurrences:
        MemorySanitizer: use-of-uninitialized-value
Platforms tested:
    Linux/64 (jelly)
    Linux/64 (platypus)

src/H5MF.c

@@ -2645,6 +2645,10 @@ H5MF_settle_raw_data_fsm(H5F_t *f, hbool_t *fsm_settled)
     HDassert(f->shared);
     HDassert(fsm_settled);
 
+    /* Initialize structs */
+    HDmemset(&fsinfo, 0, sizeof(fsinfo));
+    HDmemset(&fs_stat, 0, sizeof(fs_stat));
+
     /*
      * Only need to settle things if we are persisting free space and
      * the private property in f->shared->null_fsm_addr is not enabled.

test/dsets.c

@@ -11334,6 +11334,9 @@ test_bt2_hdr_fd(const char *env_h5_driver, hid_t fapl)
 
     TESTING("Version 2 B-tree chunk index header flush dependencies handled correctly");
 
+    /* Initialize struct */
+    HDmemset(&info, 0, sizeof(info));
+
     /* Skip this test if SWMR I/O is not supported for the VFD specified
      * by the environment variable.
      */