8311964: Some jtreg tests failing on x86 with error 'unrecognized VM options' (C2 flags)

Reviewed-by: dhanalla, thartmann

Author: singhnitin

test/hotspot/jtreg/compiler/loopopts/TestBackedgeLoadArrayFillMain.java

@@ -28,6 +28,7 @@
  * @summary ArrayFill: if store is on backedge, last iteration is not to be executed.
  * @library /test/lib
  * @compile TestBackedgeLoadArrayFill.jasm
+ * @requires vm.compiler2.enabled
  * @run main/othervm
  *      -XX:CompileCommand=compileonly,TestBackedgeLoadArrayFill*::test*
  *      -XX:-TieredCompilation -Xcomp -XX:+OptimizeFill

test/hotspot/jtreg/compiler/loopopts/TestInfiniteLoopWithUnmergedBackedgesMain.java

@@ -26,6 +26,7 @@
  * @bug 8296412
  * @compile TestInfiniteLoopWithUnmergedBackedges.jasm
  * @summary Infinite loops may not have the backedges merged, before we call IdealLoopTree::check_safepts
+ * @requires vm.compiler2.enabled
  * @run main/othervm -Xcomp -XX:-TieredCompilation -XX:-LoopUnswitching
  *      -XX:CompileCommand=compileonly,TestInfiniteLoopWithUnmergedBackedges::test*
  *      TestInfiniteLoopWithUnmergedBackedgesMain

test/hotspot/jtreg/compiler/rangechecks/TestRangeCheckCmpUOverflowVsSub.java

@@ -25,6 +25,7 @@
  * @test
  * @bug 8299959
  * @summary In CmpU::Value, the sub computation may be narrower than the overflow computation.
+ * @requires vm.compiler2.enabled
  *
  * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+StressCCP -Xcomp -XX:-TieredCompilation
  *                   -XX:CompileCommand=compileonly,compiler.rangechecks.TestRangeCheckCmpUOverflowVsSub::test