Rename MetadataProvider to InputMetadataProvider and MetadataHandler to OutputMetadataStore.

This is to better underline that one deals with action inputs, the other, with action outputs.

This change was generated mostly mechanically using my IDE, with manual tweaks to fix up the annoying "/* parameterName= */" comments.

RELNOTES: None.
PiperOrigin-RevId: 523743519
Change-Id: Ia7a67ad4296e82c31d50f47045663f2a6f151299
diff --git a/src/main/java/com/google/devtools/build/lib/exec/StandaloneTestStrategy.java b/src/main/java/com/google/devtools/build/lib/exec/StandaloneTestStrategy.java
index 241e51c..2afb45f 100644
--- a/src/main/java/com/google/devtools/build/lib/exec/StandaloneTestStrategy.java
+++ b/src/main/java/com/google/devtools/build/lib/exec/StandaloneTestStrategy.java
@@ -716,12 +716,12 @@
       }
       var unused =
           actionExecutionContext
-              .getMetadataHandler()
+              .getOutputMetadataStore()
               .getOutputMetadata(testAction.getCoverageDirectoryTreeArtifact());
 
       ImmutableSet<? extends ActionInput> expandedCoverageDir =
           actionExecutionContext
-              .getMetadataHandler()
+              .getOutputMetadataStore()
               .getTreeArtifactChildren(
                   (SpecialArtifact) testAction.getCoverageDirectoryTreeArtifact());
       Spawn coveragePostProcessingSpawn =