Fix '32-bit value shift followed by expansion to 64-bit' code defect

Fix '32-bit value shift followed by expansion to 64-bit' code defect

* gcj_mlc.c [GC_GCJ_SUPPORT] (GC_core_gcj_malloc,
GC_gcj_malloc_ignore_off_page): Cast lg local variable to word before
passing it to GRANULES_TO_BYTES (so that value type widening does not
occur after the value left shift).
* malloc.c (GC_generic_malloc_inner, GC_malloc_kind_global,
GC_generic_malloc_uncollectable): Likewise.
* typd_mlc.c (GC_malloc_explicitly_typed_ignore_off_page): Likewise.
* misc.c (block_add_size): Cast hhdr->hb_sz to word before passing it
to WORDS_TO_BYTES; cast HBLKSIZE-1 to word before "~" operation.