Fix tests to use correct fixtures for configuring (Apex)BootJars.

This is in preparation to r.android.com/1740313 where setting correct
variables would be enforced (i.e. apex and non-apex boot jars must be in
config.ApexBootJars and config.BootJars correspondingly).

Bug: 191369843
Test: m nothing
Change-Id: Ic86680c1f7af53d229083b2cc58beb3ceccb4b6a

java/bootclasspath_fragment_test.go

@@ -164,6 +164,7 @@ func TestBootclasspathFragment_Coverage(t *testing.T) {
 		prepareForTestWithBootclasspathFragment,
 		PrepareForTestWithJavaSdkLibraryFiles,
 		FixtureWithLastReleaseApis("mysdklibrary", "mycoveragestubs"),
+		FixtureConfigureApexBootJars("someapex:mybootlib"),
 		prepareWithBp,
 	)
 
@@ -186,6 +187,7 @@ func TestBootclasspathFragment_StubLibs(t *testing.T) {
 		prepareForTestWithBootclasspathFragment,
 		PrepareForTestWithJavaSdkLibraryFiles,
 		FixtureWithLastReleaseApis("mysdklibrary", "myothersdklibrary", "mycoreplatform"),
+		FixtureConfigureApexBootJars("someapex:mysdklibrary"),
 	).RunTestWithBp(t, `
 		bootclasspath_fragment {
 			name: "myfragment",