build.py will not accept --arch=dartc soon, so removing references and uses of --arch=dartc in th...

compiler/scripts/build_dartc_for_perf_metrics

 #!/bin/sh
 #
 # Produce a build of dartc that can be used to measure its performance over
 # time.  This script needs to be backwards compatible with earlier
 # revisions.
 #
 # TODO: Still need to handle revisions between r2694 and r2764.
 # 
 DARTC_REVISION=$1
 USERNAME=$2
 PASSWORD=$3
 
 # Checkout the depot tools
 svn checkout --quiet http://src.chromium.org/svn/trunk/tools/depot_tools depot_tools
 GCLIENT_CMD=./depot_tools/gclient
 
 # Make a gclient with the compiler deps only
 $GCLIENT_CMD config https://dart.googlecode.com/svn/branches/bleeding_edge/deps/compiler.deps
 
 # Make sure that we have access
 svn ls --username $USERNAME --password "$PASSWORD" https://dart.googlecode.com/svn/
 
 # Try to sync to a particular revision transitively; muffle the output
 $GCLIENT_CMD sync -r $DARTC_REVISION -t > gclient.sync.txt
 
 # Build dartc
 cd compiler
-../tools/build.py --mode release --arch dartc
+../tools/build.py --mode release
 rc=$?
 if [ $rc -ne 0 ]; then
   exit $rc
 fi
 
 # Give the metrics system a backwards compatible way of getting to the 
 # artifacts that it needs.
 cd ..
 mkdir -p prebuilt
 cd prebuilt
 COMPILER_OUTDIR=../compiler/out/Release_dartc
 cp -r $COMPILER_OUTDIR/compiler ./compiler
 GENERATED_SCRIPT_DIR=obj.target/geni/dartc
 PATH_TO_METRICS_SCRIPT=$COMPILER_OUTDIR/$GENERATED_SCRIPT_DIR
 cp -r $PATH_TO_METRICS_SCRIPT/dartc_run.sh .
 cp -r $PATH_TO_METRICS_SCRIPT/dartc_size.sh .
 cp $COMPILER_OUTDIR/d8 .
 if [ -e $PATH_TO_METRICS_SCRIPT/dartc_metrics.sh ]; then
   cp $PATH_TO_METRICS_SCRIPT/dartc_metrics.sh .
 fi