Do not duplicate android_log_write output to GC log file (Android)

* include/private/gc_priv.h (GC_real_print_stats): Remove macro.
* include/private/gc_priv.h (GC_print_stats): Define as external
variable (instead of a macro) for GC_ANDROID_LOG (only if not
SMALL_CONFIG).
* misc.c (GC_real_print_stats, GC_init): Replace GC_real_print_stats
back to GC_print_stats.
* misc.c (GC_printf, GC_LOG_PRINTF_IMPL, GC_warn_printf, GC_err_puts):
Do not duplicate output to GC_stdout/err, GC_log if GC_ANDROID_LOG
(after calling __android_log_write).
* misc.c (GC_LOG_PRINTF_IMPL): Remove unused "fileLogCond" argument.
* misc.c (GC_default_warn_proc): Do not duplicate output to
GC_stderr if GC_ANDROID_LOG (before __android_log_assert invocation).
Redirect WRITE to __android_log_write if GC_ANDROID_LOG (Android)
(code refactoring)

* misc.c (GC_stdout, GC_stderr, GC_log): Do not define as static
variable if GC_ANDROID_LOG.
* misc.c (GC_init): Do not allow to set GC_log and GC_stdout/err if
GC_ANDROID_LOG.
* misc.c (GC_ANDROID_LOG_TAG): Move definition (and include
android/log.h) upper to precede GC_write definition for Unix.
* misc.c (GC_stdout, GC_stderr, GC_long): Define specially
for GC_ANDROID_LOG (define to ANDROID_LOG_DEBUG/ERROR logging level).
* misc.c (WRITE): Define specially for GC_ANDROID_LOG (first argument
is used as logging level) redirecting to __android_log_write.
* misc.c (GC_printf, GC_stats_log_printf, GC_verbose_log_printf,
GC_warn_printf, GC_err_puts): Remove __android_log_write call
(unconditionally invoke WRITE instead).
* misc.c (GC_log_printf): Remove Android-specific implementation (use
general instead).
* misc.c (GC_stats_log_printf, GC_verbose_log_printf): Expand
GC_LOG_PRINTF_IMPL macro.
* misc.c (GC_LOG_PRINTF_IMPL): Remove macro.
Replace GC_stats_log_printf with GC_DBG/INFOLOG_PRINTF
(minimize logging for Android when print_stats is off)

* alloc.c (GC_try_to_collect_inner, GC_stopped_mark,
GC_finish_collection): Use GC_log_printf instead of
GC_stats_log_printf.
* finalize.c (GC_print_finalization_stats): Likewise.
* include/private/gc_priv.h (GC_COND_LOG_PRINTF): Likewise.
* alloc.c (GC_stopped_mark): Use GC_DBGLOG_PRINTF instead of
GC_COND_LOG_PRINTF (useful for Android).
* alloc.c (GC_expand_hp_inner): Reformat comment.
* alloc.c (GC_expand_hp_inner): Use GC_INFOLOG_PRINTF instead of
GC_COND_LOG_PRINTF (useful for Android).
* include/private/gc_priv.h (GC_stats_log_printf): Remove (macro and
prototype).
* include/private/gc_priv.h (GC_DBGLOG_PRINTF, GC_INFOLOG_PRINTF):
New macro (redirecting either to GC_COND_LOG_PRINTF or to
GC_log_printf/GC_info_log_printf if GC_ANDROID_LOG).
* include/private/gc_priv.h (GC_info_log_printf): New prototype (only
if GC_ANDROID_LOG).
* misc.c (GC_stats_log_printf): Rename to GC_info_log_printf.
Improve logged messages about heap size and usage

* alloc.c (GC_stopped_mark): Print heap size to debug log in KiB
(using TO_KiB_UL macro) excluding unmapped memory size.
* alloc.c (GC_compute_heap_usage_percent): New inline function.
* alloc.c (GC_finish_collection): Use GC_DBGLOG_PRINTF instead of
GC_COND_LOG_PRINTF for heap usage logging; print heap usage in KiB;
log memory heap utilization in percent (using
GC_compute_heap_usage_percent).
* alloc.c (GC_expand_hp_inner): Log increased heap size (in KiB)
instead of increment size.
* include/private/gc_priv.h (TO_KiB_UL): New macro.
Turn on world-stop delay logging at debug level by default for Android

* alloc.c (GC_stopped_mark): Use GC_PRINT_STATS_FLAG instead of
GC_print_stats in the condition for logging world-stop pause time.
* include/private/gc_priv.h (GC_PRINT_STATS_FLAG): New macro (defined
as !GC_quiet if GC_ANDROID_LOG otherwise as GC_print_stats.
* include/private/gc_priv.h (GC_DBGLOG_PRINTF): Define using
GC_PRINT_STATS_FLAG instead of GC_quiet; update comment.