Concatenate string literals at compile time.

This CL was generated by running:
git ls-files | grep ".cc" | xargs perl -i -ne 'BEGIN {undef $/}; s/("[\s\n]*<<[\s\n]*")/" "/g; print;'; git cl format

After that I manually edited modules/audio_processing/gain_controller2.cc to preserve its original
formatting.

This primary benefit of this change is a small reduction in binary size.

Bug: None
Change-Id: I689fa7ba9c717c314bb167e5d592c3c4e0871e29
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/165961
Reviewed-by: Alessio Bazzica <alessiob@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Commit-Queue: Jonas Olsson <jonasolsson@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#30251}

modules/audio_processing/include/audio_processing.cc

@@ -72,13 +72,16 @@ std::string AudioProcessing::Config::ToString() const {
   char buf[1024];
   rtc::SimpleStringBuilder builder(buf);
   builder << "AudioProcessing::Config{ "
-          << "pipeline: {"
-          << "maximum_internal_processing_rate: "
+             "pipeline: {"
+             "maximum_internal_processing_rate: "
           << pipeline.maximum_internal_processing_rate
-          << ", multi_channel_render: " << pipeline.multi_channel_render << ", "
-          << ", multi_channel_capture: " << pipeline.multi_channel_capture
+          << ", multi_channel_render: " << pipeline.multi_channel_render
+          << ", "
+             ", multi_channel_capture: "
+          << pipeline.multi_channel_capture
           << "}, "
-          << "pre_amplifier: { enabled: " << pre_amplifier.enabled
+             "pre_amplifier: { enabled: "
+          << pre_amplifier.enabled
           << ", fixed_gain_factor: " << pre_amplifier.fixed_gain_factor
           << " }, high_pass_filter: { enabled: " << high_pass_filter.enabled
           << " }, echo_canceller: { enabled: " << echo_canceller.enabled