Try to reduce flakiness in JvmGcMetricsTest.gcTimingIsCorrectForPauseCycleCollectors() (#5996)

Signed-off-by: Johnny Lim <[email protected]>

Author: izeye

micrometer-core/src/test/java/io/micrometer/core/instrument/binder/jvm/JvmGcMetricsTest.java

@@ -104,6 +104,10 @@ void gcMetricsAvailableAfterGc() {
     // in an LTS is 17
     @EnabledForJreRange(min = JRE.JAVA_17)
     void gcTimingIsCorrectForPauseCycleCollectors() {
+        // Try to reduce chances for GCs to happen between collecting initial values and
+        // binding metrics.
+        System.gc();
+
         // get initial GC timing metrics from JMX, if any
         // GC could have happened before this test due to testing infrastructure
         // If it did, it will not be captured in the metrics