hg: build-infra/jdk8: Add bin/shell-tracer.sh which wraps the shell when running with LOG=trace

[magnus.ihse.bursie at oracle.com]

Changeset: 545020b2390d
Author:    ihse
Date:      2012-10-10 21:37 +0200
URL:       http://hg.openjdk.java.net/build-infra/jdk8/rev/545020b2390d

Add bin/shell-tracer.sh which wraps the shell when running with LOG=trace
and add simple logging of time spent per command executed. (Thanks to Jon
Gibbons for the idea!)

! common/autoconf/basics.m4
! common/autoconf/generated-configure.sh
! common/autoconf/spec.gmk.in
+ common/bin/shell-tracer.sh
! common/makefiles/MakeBase.gmk
! common/makefiles/Makefile