build(ngc): run integration test hermetically

This ensures we run in a clean directory, using our real distribution. It finds bugs like @internal
APIs needed to type-check in the offline compiler, as well as problems in package.json.

Also move tsc-wrapped under tools/@angular

build.sh

@@ -35,7 +35,7 @@ cd -
 TSCONFIG=./modules/tsconfig.json
 echo "====== (all)COMPILING: \$(npm bin)/tsc -p ${TSCONFIG} ====="
 # compile ts code
-TSC="node dist/tools/tsc-wrapped/src/main"
+TSC="node dist/tools/@angular/tsc-wrapped/src/main"
 $TSC -p modules/tsconfig.json
 
 rm -rf ./dist/packages-dist