Enhancement to the tool h5clear (HDFFV-10360)

tools/test/misc/testfiles/h5clear_usage.ddl

@@ -4,7 +4,9 @@ usage: h5clear [OPTIONS] file_name
    -V, --version             Print version number and exit
    -s, --status              Clear the status_flags field in the file's superblock
    -m, --image               Remove the metadata cache image from the file
-
+   --filesize                Print the file's EOA and EOF
+   --increment=C             Set the file's EOA to the maximum of (EOA, EOF) + C for the file <file_name>
+                             C is >= 0; C is optional and will default to 1M when not set
 Examples of use:
 
 h5clear -s file_name
@@ -12,3 +14,9 @@ h5clear -s file_name
 
 h5clear -m file_name
   Remove the metadata cache image from the HDF5 file <file_name>.
+
+h5clear --increment file_name
+  Set the EOA to the maximum of (EOA, EOF) + 1M for the file <file_name>.
+
+h5clear --increment=512 file_name
+  Set the EOA to the maximum of (EOA, EOF) + 512 for the file <file_name>.