Disable TBB by default

This disables TBB by default in the bootstrap script.

Using our `/test/benchmarking` benchmarks, there is no discernible difference
between the end-to-end execution times or the individual execution times of the
parallel functions. For example, here is are the results of the `bench_large_io`
between the two:

// Without TBB
end-to-end: 267829 ms
`parallel_for`: 271120 ms
`parallel_for_2d`: 104 ms
`parallel_sort`: 14447 ms

// With TBB
end-to-end: 269911 ms
`parallel_for`: 273447 ms
`parallel_for_2d`: 107 ms
`parallel_sort`: 14382 ms

Note that the "end-to-end" was measured with a different timing mechanism than
the individual function timers. The individual function timers are also
cumulative per thread.

azure-pipelines.yml

@@ -49,7 +49,6 @@ stages:
           linux_asan:
             imageName: 'ubuntu-16.04'
             TILEDB_CI_ASAN: ON
-            TILEDB_TBB: OFF
             TILEDB_SERIALIZATION: ON
             CXX: g++-7
           linux_serialization:

bootstrap

@@ -89,7 +89,7 @@ tiledb_werror="ON"
 tiledb_tests="ON"
 tiledb_cpp_api="ON"
 tiledb_force_all_deps="OFF"
-tiledb_tbb="ON"
+tiledb_tbb="OFF"
 tiledb_stats="ON"
 tiledb_static="OFF"
 tiledb_disable_avx2=""

scripts/azure-linux_mac-release.yml

@@ -68,8 +68,8 @@ steps:
     if [[ "$TILEDB_GCS" == "ON" ]]; then
       bootstrap_args="${bootstrap_args} --enable-gcs";
     fi;
-    if [[ "$TILEDB_TBB" == "OFF" ]]; then
-      bootstrap_args="${bootstrap_args} --disable-tbb";
+    if [[ "$TILEDB_TBB" == "ON" ]]; then
+      bootstrap_args="${bootstrap_args} --enable-tbb";
     fi
     if [[ "$TILEDB_TOOLS" == "ON" ]]; then
       bootstrap_args="${bootstrap_args} --enable-tools";

scripts/azure-linux_mac.yml

@@ -100,8 +100,8 @@ steps:
     if [[ "$TILEDB_GCS" == "ON" ]]; then
       bootstrap_args="${bootstrap_args} --enable-gcs";
     fi;
-    if [[ "$TILEDB_TBB" == "OFF" ]]; then
-      bootstrap_args="${bootstrap_args} --disable-tbb";
+    if [[ "$TILEDB_TBB" == "ON" ]]; then
+      bootstrap_args="${bootstrap_args} --enable-tbb";
     fi
     if [[ "$TILEDB_TOOLS" == "ON" ]]; then
       bootstrap_args="${bootstrap_args} --enable-tools";