RFR: JDK-8146977 ove the output "Building configuration X (matching Y)" to lower log level

[Magnus Ihse Bursie]

The output "Building configuration X (matching Y)" is not needed when 
using the build system at the default log level because the build system 
always writes "Building target 'Z' in configuration 'Y'", so the user 
already knows the configuration being used.

Bug: https://bugs.openjdk.java.net/browse/JDK-8146977
Patch inline:
diff --git a/make/InitSupport.gmk b/make/InitSupport.gmk
--- a/make/InitSupport.gmk
+++ b/make/InitSupport.gmk
@@ -279,7 +279,9 @@
            # generated files.
            ifeq ($$(MAKE_RESTARTS),)
              ifeq ($$(words $$(matching_confs)), 1)
-              $$(info Building configuration '$$(matching_confs)' 
(matching CONF=$$(CONF)))
+              ifneq ($$(findstring $$(LOG_LEVEL), info debug trace),)
+                $$(info Building configuration '$$(matching_confs)' 
(matching CONF=$$(CONF)))
+              endif
              else
                $$(info Building these configurations (matching CONF=$$(CO

/Magnus